Photocurrent and electronic activities of oriented-his-tagged photosynthetic light-harvesting/reaction center core complexes assembled onto a gold electrode

Kondo, M. et al. (2012) Photocurrent and electronic activities of oriented-his-tagged photosynthetic light-harvesting/reaction center core complexes assembled onto a gold electrode. Biomacromolecules, 13(2), pp. 432-438. (doi:10.1021/bm201457s)

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Publisher's URL: http://dx.doi.org/10.1021/bm201457s

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.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Cogdell, Professor Richard and Gardiner, Dr Alastair
Authors: Kondo, M., Iida, K., Dewa, T., Tanaka, H., Ogawa, T., Nagashima, S., Nagashima, K.V.P., Shimada, K., Hashimoto, H., Gardiner, A.T., Cogdell, R.J., and Nango, M.
College/School:College of Medical Veterinary and Life Sciences
College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
Journal Name:Biomacromolecules
ISSN:1525-7797
ISSN (Online):1526-4602
Published Online:12 January 2012

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