Molecular imaging of lipid layers containing calixarene-cytochrome c complexes
|Alexandra Poturnayová 1, Maja Snejdarkova 2, Isabel Neundlinger , Andreas Ebner , Tibor Hianik 3|
1. Institute of Animal Biochemistry and Genetics SASc, Moyzesova 61, Ivanka pri Dunaji 90028, Slovakia (Slovak Rep.)
The vesicles and supported bilayer lipid membranes are convenient models of biomembranes. The lipid films could be modified by proteins or synthetic receptors and serve as a recognition devices for medical diagnosis. Calixarenes (CX) are being used for detection of a wide range of compounds such as metal ions, amino acids or proteins. Recently CX specific to cytochrome c (cyt c) has been developed . Cyt c participates in electron transport and it is responsible for activation of the apoptotic pathway through releasing from mitochondria into the cytosol. In particularly it has been shown that cyt c induced transition of lamellar phase composed of phosphatidylcholine, which is favorable for transport of cyt c through hydrophobic part of the membrane. The detection of endogenous concentration of cyt c is of high importance for diagnosis of possible pathological processes in the organism. By atomic force microscopy we studied the topography of the self assembled lipid films composed of dimiristoylphosphatidylcholine (DMPC) contained CX and formed on freshly cleaved mica surface. The height difference between mica surface and upper part of DMPC layer was between 3 and 4 nm, which correspond to the lipid bilayer and agrees well with results published earlier. Interesting result were obtained for the layers incubated with 30 nM cyt c. The roughness of CX layer was about 5 times higher in comparison with that of DMPC, probably due to formation of monolayers and even multilayers of CX. Novel and surprising result has been obtained for mixed DMPC-CX layers at presence of cyt c. Incubation of these layers with 30 nM of cyt c resulted in transformation of rather rough multilayers into the relatively flat layers contained sharp fibers of cyt c.
Acknowledgments. This work was financially supported by Slovak Research and Development Agency (Projects VVCE-0064-07, APVV-0410-10) and by project MNT-ERA.NET II project IntelliTip (ID 431, AN 234989 to M.Š. and FFG project 823980 I.N to A.E.). We thank to Dr. T. Oshima for generous gift of CX.
1 Oshima, T., Ishii, T., Baba, Y., Higuchi, H., Ohto, K., Inoue, K. Solv. Extr. Res. Dev. Japan 15 (2008), 89-98
Presentation: Poster at SMCBS'2011 International Workshop, by Alexandra Poturnayová
See On-line Journal of SMCBS'2011 International Workshop
Submitted: 2011-09-16 10:19 Revised: 2011-09-21 17:21