Bacteriorhodopsin (bR) as an electronic conduction medium: Current transport through bR-containing monolayers Export

@article{citeulike:2397038, abstract = {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. 10.1073/pnas.0511234103}, author = {Jin, Yongdong and Friedman, Noga and Sheves, Mordechai and He, Tao and Cahen, David}, citeulike-article-id = {2397038}, citeulike-linkout-0 = {http://dx.doi.org/10.1073/pnas.0511234103}, citeulike-linkout-1 = {http://www.pnas.org/cgi/content/abstract/103/23/8601}, citeulike-linkout-2 = {http://view.ncbi.nlm.nih.gov/pubmed/16731629}, citeulike-linkout-3 = {http://www.hubmed.org/display.cgi?uids=16731629}, day = {6}, doi = {10.1073/pnas.0511234103}, journal = {Proceedings of the National Academy of Sciences}, keywords = {bacteriorhodopsin, nanotech}, month = {June}, number = {23}, pages = {8601--8606}, posted-at = {2008-02-19 02:51:56}, priority = {2}, title = {Bacteriorhodopsin (bR) as an electronic conduction medium: Current transport through bR-containing monolayers}, url = {http://dx.doi.org/10.1073/pnas.0511234103}, volume = {103}, year = {2006} }

TY - JOUR ID - citeulike:2397038 L3 - citeulike-article-id:2397038 N2 - 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. 10.1073/pnas.0511234103 IS - 23 JF - Proceedings of the National Academy of Sciences EP - 8606 TI - Bacteriorhodopsin (bR) as an electronic conduction medium: Current transport through bR-containing monolayers VL - 103 SP - 8601 KW - bacteriorhodopsin KW - nanotech AU - Jin, Yongdong AU - Friedman, Noga AU - Sheves, Mordechai AU - He, Tao AU - Cahen, David PY - 2006/06/06/ UR - http://dx.doi.org/10.1073/pnas.0511234103 ER -