Document Detail


Bacteriorhodopsin (bR) as an electronic conduction medium: current transport through bR-containing monolayers.
MedLine Citation:
PMID:  16731629     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Studying electron transport (ET) through proteins is hampered by achieving reproducible experimental configurations, particularly electronic contacts to the proteins. The transmembrane protein bacteriorhodopsin (bR), a natural light-activated proton pump in purple membranes of Halobacterium salinarum, is well studied for biomolecular electronics because of its sturdiness over a wide range of conditions. To date, related studies of dry bR systems focused on photovoltage generation and photoconduction with multilayers, rather than on the ET ability of bR, which is understandable because ET across 5-nm-thick, apparently insulating membranes is not obvious. Here we show that electronic current passes through bR-containing artificial lipid bilayers in solid "electrode-bilayer-electrode" structures and that the current through the protein is more than four orders of magnitude higher than would be estimated for direct tunneling through 5-nm, water-free peptides. We find that ET occurs only if retinal or a close analogue is present in the protein. As long as the retinal can isomerize after light absorption, there is a photo-ET effect. The contribution of light-driven proton pumping to the steady-state photocurrents is negligible. Possible implications in view of the suggested early evolutionary origin of halobacteria are noted.
Authors:
Yongdong Jin; Noga Friedman; Mordechai Sheves; Tao He; David Cahen
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2006-05-26
Journal Detail:
Title:  Proceedings of the National Academy of Sciences of the United States of America     Volume:  103     ISSN:  0027-8424     ISO Abbreviation:  Proc. Natl. Acad. Sci. U.S.A.     Publication Date:  2006 Jun 
Date Detail:
Created Date:  2006-06-07     Completed Date:  2006-07-19     Revised Date:  2010-09-16    
Medline Journal Info:
Nlm Unique ID:  7505876     Medline TA:  Proc Natl Acad Sci U S A     Country:  United States    
Other Details:
Languages:  eng     Pagination:  8601-6     Citation Subset:  IM    
Affiliation:
Department of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel.
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MeSH Terms
Descriptor/Qualifier:
Bacteriorhodopsins / chemistry*,  metabolism*,  ultrastructure
Electric Conductivity
Electron Transport
Halobacterium salinarum / chemistry
Models, Molecular
Purple Membrane / chemistry,  ultrastructure
Retinaldehyde / chemistry
Chemical
Reg. No./Substance:
116-31-4/Retinaldehyde; 53026-44-1/Bacteriorhodopsins
Comments/Corrections

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