Structure-dependent electrical conductivity of protein: its differences between alpha-domain and beta-domain structures

Electron transports in the ? -domain and ? -domain of proteins have been comprehensively investigated. The structure-dependent electron transport of proteins has been experimentally measured and theoretically simulated, and both the theoretical and experimental results demonstrate significant differences in electrical conductivity between the ? -domain and ? -domain. By controlling the feedback system of the scanning tunneling microscope (STM), the conductance of a single ? -domain protein hemoglobin (Hgb) and a ? -domain protein superoxide dismutase enzyme (SOD) were measured, respectively. The current signal of Hgb is obviously stronger, indicating that the ? -domain is more conductive. To confirm our finding, molecular orbitals of both the ? -domain in SOD and ? -domain in Hgb have been analyzed based on first-principles calculations. As expected, tunneling transport and hopping in the ? -domain are both more efficien...

X Y Zhang, Jian Shao, S X Jiang, Biao Wang and Yue Zheng

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