Photocurrent and electronic activities of oriented-His-tagged photosynthetic light-harvesting/reaction center core complexes assembled onto a gold electrode.
Biomacromolecules
; 13(2): 432-8, 2012 Feb 13.
Article
em En
| MEDLINE
| ID: mdl-22239547
ABSTRACT
A polyhistidine (His) tag was fused to the C- or N-terminus of the light-harvesting (LH1)-α chain of the photosynthetic antenna core complex (LH1-RC) from Rhodobacter sphaeroides to allow immobilization of the complex on a solid substrate with defined orientation. His-tagged LH1-RCs were adsorbed onto a gold electrode modified with Ni-NTA. The LH1-RC with the C-terminal His-tag (C-His LH1-RC) on the modified electrode produced a photovoltaic response upon illumination. Electron transfer is unidirectional within the RC and starts when the bacteriochlorophyll a dimer in the RC is activated by light absorbed by LH1. The LH1-RC with the N-terminal His-tag (N-His LH1-RC) produced very little or no photocurrent upon illumination at any wavelength. The conductivity of the His-tagged LH1-RC was measured with point-contact current imaging atomic force microscopy, indicating that 60% of the C-His LH1-RC are correctly oriented (N-His 63%). The oriented C-His LH1-RC or N-His LH1-RC showed semiconductive behavior, that is, had the opposite orientation. These results indicate that the His-tag successfully controlled the orientation of the RC on the solid substrate, and that the RC produced photocurrent depending upon the orientation on the electrode.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Bactérias
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Rhodobacter sphaeroides
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Materiais Biomiméticos
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Complexos de Proteínas Captadores de Luz
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Ouro
Idioma:
En
Revista:
Biomacromolecules
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
Japão