摘要
In this study, a lipid membrane was fabricated by fusing cardiolipin-phosphatidylcholine（CL_PC, 1：4） vesicles onto a hydrophobic surface of 1-dodecanethiol（DT） preadsorbed on a nanostructured gold film. By changing the concentration of the DT adsorption solution, we constructed a series of CL PC-DT bilayers with different hydrophobicity to study the effects of lipid membrane characteristics on the adsorption conformation of cytochrome c（Cyt c）. Electrochemical analysis showed that the formal potential is 0.24 V for Cyt c-CL_PC-DT（10）, 0.2 V for Cyt c-CL_PC-DT（20）, and 0.16 V for Cyt c-CL_PC-DT（40） — a gradual positive shift with the decreasing DT concentration — relative to the potential of native cyt c（0.02 V）. Potential-induced surface-enhanced infrared adsorption difference spectroscopy revealed that the gradual positive shift of the formal potential of CL-bound cyt c is determined by the environment with the gradually lowered dielectric constant for the heme cofactor in CL-bound cyt c（Fe^3＋）.
In this study, a lipid membrane was fabricated by fusing cardiolipin-phosphatidylcholine（CL_PC, 1：4） vesicles onto a hydrophobic surface of 1-dodecanethiol（DT） preadsorbed on a nanostructured gold film. By changing the concentration of the DT adsorption solution, we constructed a series of CL PC-DT bilayers with different hydrophobicity to study the effects of lipid membrane characteristics on the adsorption conformation of cytochrome c（Cyt c）. Electrochemical analysis showed that the formal potential is 0.24 V for Cyt c-CL_PC-DT（10）, 0.2 V for Cyt c-CL_PC-DT（20）, and 0.16 V for Cyt c-CL_PC-DT（40） — a gradual positive shift with the decreasing DT concentration — relative to the potential of native cyt c（0.02 V）. Potential-induced surface-enhanced infrared adsorption difference spectroscopy revealed that the gradual positive shift of the formal potential of CL-bound cyt c is determined by the environment with the gradually lowered dielectric constant for the heme cofactor in CL-bound cyt c（Fe^3＋）.
基金
Project supported by the National Natural Science Foundation of China(Grant Nos.91227114
21322510
and 21105097)
the China Postdoctoral Science Foundation(Grant No.2013M530998)
the Natural Science Foundation of Jilin Province
China(Grant No.201215092)
the President Funds of the Chinese Academy of Sciences
