Structure-dependent electrical conductivity of protein: its differences between alpha-domain and beta-domain structures.
Electron transports in the α-domain and β-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 α-domain and β-domain. By controlling the feedback system of the scanning tunneling microscope (STM), the conductance of a single α-domain protein hemoglobin (Hgb) and a β-domain protein superoxide dismutase enzyme (SOD) were measured, respectively. The current signal of Hgb is obviously stronger, indicating that the α-domain is more conductive. To confirm our finding, molecular orbitals of both the β-domain in SOD and α-domain in Hgb have been analyzed based on first-principles calculations. As expected, tunneling transport and hopping in the α-domain are both more efficient, indicating that it is easier for electrons to transport through the α-domain, which are in great agreement with our experimental data. In order to explain our results, molecular structures of α- and β-domains have been carefully analyzed and show that the explanation should lie in the differences in packing mode between the α-domain and β-domain. This research should be very important to application prospects in molecular electronics.
State Key Laboratory of Optoelectronic Materials and Technologies/Institute of Optoelectronic and Functional Composite Materials, Sun Yat-sen University, Guangzhou, 510275, People's Republic of China. Micro&Nano Physics and Mechanics Research Laboratory, School of Physic and Engineering, Sun Yat-sen University, Guangzhou, 510275, People's Republic of China. Sino-French Institute of Nuclear Engineering and Technology, Sun Yat-sen University, Zhuhai, 519082, China.
X Y
XY
Zhang
Jian
J
Shao
S X
SX
Jiang
Biao
B
Wang
Yue
Y
Zheng
D003198:Computer Simulation; D004553:Electric Conductivity; D004579:Electron Transport; D006454:Hemoglobins / Q000737:chemistry*; D006801:Humans; D016252:Microscopy, Scanning Tunneling / Q000379:methods; D017434:Protein Structure, Tertiary; D013482:Superoxide Dismutase / Q000737:chemistry*; D000072105:Superoxide Dismutase-1
D006454:Hemoglobins; C000606290:SOD1 protein, human; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1