351. AFM and TEM observations of alpha-helix to beta-sheet conformational change occurring on carbon nanotubes.
- Author
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Sugiyama Y, Inoue Y, Muneyuki E, Haneda H, and Fujimoto M
- Subjects
- Protein Folding, Protein Structure, Secondary, Bacteriorhodopsins ultrastructure, Microscopy, Atomic Force methods, Microscopy, Electron, Transmission methods, Nanotubes, Carbon
- Abstract
Bacteriorhodopsin (BR), which is rich in alpha-helical structure, was spread onto water with single-wall carbon nanotubes (SCNTs). After a Langmuir trough was used to apply compressive surface pressure to maintain the alpha-helices monolayer of denatured BR, the composite films comprising alpha-helices and SCNTs were transferred horizontally onto substrates. Atomic force microscopy (AFM) and fluorescence microscopy observation suggested that alpha-helices in contact with SCNTs changed into beta-sheets. High-resolution transmission electron microscopy (HR-TEM) showed 0.54 nm periodicity characteristic of the turn of alpha-helical structure in the SCNTs-free alpha-helix monolayer region and showed the 0.70 nm periodicity of beta-sheet pleated structure in the region where SCNTs were covered with unfolded BR. Unique features of carbon nanotubes that trigger conformational changes of a protein were revealed.
- Published
- 2006
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