PMID:12101014
| Citation |
Killig, F and Stark, G (2002) Photodynamic activation of ion transport through lipid membranes and its correlation with an increased dielectric constant of the membrane. Biochim. Biophys. Acta 1564:207-13 |
|---|---|
| Abstract |
Illumination of biological membranes with visible light in the presence of membrane-active sensitizers (e.g. rose bengal) is known to inactivate transport proteins such as ion channels and ion pumps. In some cases, however, illumination gives rise to an activation of transport. This is shown here for ion channels formed by alamethicin in lipid membranes, and for porin channels, which were isolated from the outer membrane of E. coli (OmpC) and from the outer membrane of mitochondria (VDAC) and were reconstituted in lipid membranes. An activation (in the form of an increased conductance) was also observed in the presence of the cation carriers valinomycin and nonactin. The activation phenomena were only present, if the membranes were made from lipids containing unsaturated double bonds. Activation was reduced in the presence of the antioxidant vitamin E. We suggest that the activation of the different transport systems has a common physical basis, namely an increase of the dielectric constant, epsilon(m), of the membrane interior by the presence of polar oxidation products of photodynamically induced lipid peroxidation. Experimental evidence for an enhanced dielectric constant was obtained from the finding of a light-induced increase of the membrane capacitance in the presence of rose bengal. |
| Links | |
| Keywords |
Electrochemistry; Ion Transport/radiation effects; Membrane Lipids/chemistry; Membrane Lipids/metabolism; Membrane Lipids/radiation effects; Photochemistry; Photosensitizing Agents; Porins/chemistry; Porins/metabolism; Porins/radiation effects; Rose Bengal; Voltage-Dependent Anion Channels |
| edit table |
Significance
You can help EcoliWiki by summarizing why this paper is useful
Useful Materials and Methods
You can help Ecoliwiki by describing the useful materials (strains, plasmids, antibodies, etc) described in this paper.
Annotations
<annotationlinks/>
EcoliWiki Links
Add links to pages that link here (e.g. gene, product, method pages)
References
See Help:References for how to manage references in EcoliWiki.