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Mechanisms for the direct electron transfer of cytochrome c induced by multi-walled carbon nanotubes.

Zhao HZ, Du Q, Li ZS, Yang QZ - Sensors (Basel) (2012)

Bottom Line: There are several possible mechanisms that explain the DET of Cyt c.In the presence of MWCNTs, the secondary structure of Cyt c changes, which exposes the active site, then, the orientation of the heme is optimized, revolving the exposed active center to the optimum spatial orientation for DET; and finally, a transition of spin states is induced, providing relatively high energy and a more open microenvironment for electron transfer.These changes at different nano-levels are closely connected and form a complex process that promotes the electron transfer of Cyt c.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Engineering, Peking University, Beijing 100871, China. zhaohuazhang@pku.edu.cn

ABSTRACT
Multi-walled carbon nanotube (MWCNT)-modified electrodes can promote the direct electron transfer (DET) of cytochrome c (Cyt c). There are several possible mechanisms that explain the DET of Cyt c. In this study, several experimental methods, including Fourier transform infrared spectroscopy, circular dichroism, ultraviolet-visible absorption spectroscopy, and electron paramagnetic resonance spectroscopy were utilized to investigate the conformational changes of Cyt c induced by MWCNTs. The DET mechanism was demonstrated at various nano-levels: secondary structure, spatial orientation, and spin state. In the presence of MWCNTs, the secondary structure of Cyt c changes, which exposes the active site, then, the orientation of the heme is optimized, revolving the exposed active center to the optimum spatial orientation for DET; and finally, a transition of spin states is induced, providing relatively high energy and a more open microenvironment for electron transfer. These changes at different nano-levels are closely connected and form a complex process that promotes the electron transfer of Cyt c.

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Amide I band peak fitting in the original FTIR spectra for Cyt c (A) and Cyt c/MWCNTs (B). The original envelope (□), the component bands (dashed line), and the generated envelope (solid line) are shown, respectively.
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f3-sensors-12-10450: Amide I band peak fitting in the original FTIR spectra for Cyt c (A) and Cyt c/MWCNTs (B). The original envelope (□), the component bands (dashed line), and the generated envelope (solid line) are shown, respectively.

Mentions: The slight shift of the amide I and amide II bands of Cyt c absorbed on MWCNTs indicates a corresponding change in secondary structure. Deconvolution of the amide I band of Cyt c before and after absorption onto MWCNTs followed by curve fitting with a Gaussian function yields several distinct underlying absorption bands shown in Figure 3.


Mechanisms for the direct electron transfer of cytochrome c induced by multi-walled carbon nanotubes.

Zhao HZ, Du Q, Li ZS, Yang QZ - Sensors (Basel) (2012)

Amide I band peak fitting in the original FTIR spectra for Cyt c (A) and Cyt c/MWCNTs (B). The original envelope (□), the component bands (dashed line), and the generated envelope (solid line) are shown, respectively.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472837&req=5

f3-sensors-12-10450: Amide I band peak fitting in the original FTIR spectra for Cyt c (A) and Cyt c/MWCNTs (B). The original envelope (□), the component bands (dashed line), and the generated envelope (solid line) are shown, respectively.
Mentions: The slight shift of the amide I and amide II bands of Cyt c absorbed on MWCNTs indicates a corresponding change in secondary structure. Deconvolution of the amide I band of Cyt c before and after absorption onto MWCNTs followed by curve fitting with a Gaussian function yields several distinct underlying absorption bands shown in Figure 3.

Bottom Line: There are several possible mechanisms that explain the DET of Cyt c.In the presence of MWCNTs, the secondary structure of Cyt c changes, which exposes the active site, then, the orientation of the heme is optimized, revolving the exposed active center to the optimum spatial orientation for DET; and finally, a transition of spin states is induced, providing relatively high energy and a more open microenvironment for electron transfer.These changes at different nano-levels are closely connected and form a complex process that promotes the electron transfer of Cyt c.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Engineering, Peking University, Beijing 100871, China. zhaohuazhang@pku.edu.cn

ABSTRACT
Multi-walled carbon nanotube (MWCNT)-modified electrodes can promote the direct electron transfer (DET) of cytochrome c (Cyt c). There are several possible mechanisms that explain the DET of Cyt c. In this study, several experimental methods, including Fourier transform infrared spectroscopy, circular dichroism, ultraviolet-visible absorption spectroscopy, and electron paramagnetic resonance spectroscopy were utilized to investigate the conformational changes of Cyt c induced by MWCNTs. The DET mechanism was demonstrated at various nano-levels: secondary structure, spatial orientation, and spin state. In the presence of MWCNTs, the secondary structure of Cyt c changes, which exposes the active site, then, the orientation of the heme is optimized, revolving the exposed active center to the optimum spatial orientation for DET; and finally, a transition of spin states is induced, providing relatively high energy and a more open microenvironment for electron transfer. These changes at different nano-levels are closely connected and form a complex process that promotes the electron transfer of Cyt c.

Show MeSH