Structure and Physicochemical Properties of Phospholipidic Monolayers and Bilayers. LB and AFM Studies

Abstract

[eng] The main objective of this Ph. D. Thesis work was to study the physicochemical properties of the inner membrane of mitochondria and the interaction of "cyt c" with model membranes. Suitable techniques were used to accomplish this objective: Langmuir and Langmuir Blodgett films, fluorescence spectroscopy, Brewster Angle Microscopy and Atomic Force Microscopy. The general conclusion of this Thesis is: "Calcium induces HII phases in POPE:CL (0.8:0.2, mol:mol) samples in solution. This composition is the most stable mixed monolayer of both phospholipids and corresponds to the native molar fraction in the inner membrane of the mitochondrion. The extension of these inverted micelles forms planar bilayers on solid supports displaying lateral lipid segregation of CL enriched domains where cyt "c can" bind specifically. In this configuration POPC can remain as a spacer in POPE enriched domains forming the matrix of the membrane". The inverse process would be a possible vindication to the release of "cyt c" from the inner membrane of mitochondrion during apoptosis.