| Autor: |
Cañadas O; Department of Biochemistry and Molecular Biology I, Complutense University of Madrid, Madrid, Spain., García-Verdugo I, Keough KM, Casals C |
| Jazyk: |
angličtina |
| Zdroj: |
Biophysical journal [Biophys J] 2008 Oct; Vol. 95 (7), pp. 3287-94. Date of Electronic Publication: 2008 Jul 03. |
| DOI: |
10.1529/biophysj.108.137323 |
| Abstrakt: |
Surfactant protein A (SP-A) is known to cause bacterial permeabilization. The aim of this work was to gain insight into the mechanism by which SP-A induces permeabilization of rough lipopolysaccharide (Re-LPS) membranes. In the presence of calcium, large interconnected aggregates of fluorescently labeled TR-SP-A were observed on the surface of Re-LPS films by epifluorescence microscopy. Using Re-LPS monolayer relaxation experiments at constant surface pressure, we demonstrated that SP-A induced Re-LPS molecular loss by promoting the formation of three-dimensional lipid-protein aggregates in Re-LPS membranes. This resulted in decreased van der Waals interactions between Re-LPS acyl chains, as determined by differential scanning calorimetry, which rendered the membrane leaky. We also showed that the coexistence of gel and fluid lipid phases within the Re-LPS membrane conferred susceptibility to SP-A-mediated permeabilization. Taken together, our results seem to indicate that the calcium-dependent permeabilization of Re-LPS membranes by SP-A is related to the extraction of LPS molecules from the membrane due to the formation of calcium-mediated protein aggregates that contain LPS. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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