Adsorption of cytochrome c to phospholipid monolayers studied by reflection spectroscopy

Abstract

The uptake of cytochrome c by charged and neutral lipid monolayers was studied by using reflection spectroscopy. The method was shown to be a very sensitive and useful technique in studies of lipid-protein interactions. It was found that cytochrome c is preferentially bound to monolayers of negatively charged monolayers in the solid phase. Polarized light under oblique incidence was used to determine the average orientation of chromophores in cytochrome c bound to lipid monolayer. The transition moments of chromophore are oriented parallel to the monolayer plane.

Interaction of nitrophenols with lipids at the air/water interface

“…The dominant role of electrostatic interactions seen here has also been found in previous studies of lipid protein interactions [16,17]. All these studies show a different kinetics for changes in AH and AR with time depending on monolayer density.…”

“…The method [4] is based on the modification of light reflection from the air/water interface due to the presence of chromophores at the interface. This technique has been used to study the adsorption of dyes [13][14][15], and lipid-protein interactions at the air/solution interface [16][17][18]. It provides independent information on the density and orientation of the bound molecules.…”

Adsorption of anionic polyelectrolytes to dioctadecyldimethylammonium bromide monolayers

“…Therefore, long exchange times are necessary [13]. Fromherz has reported a method in which the monolayer is prepared on one compartment of a multi-compartment trough which contains pure water and subsequently transferred to another compartment which contains a polyelectrolyte or enzyme solution [14][15][16][17][18][19] (see Fig. 1).…”

“…Examples are: the change in the surface pressure (at constant area) [14,15,[17][18][19], changes in UV/vis spectra [8], and changes in the reflectivity at the Brewster angle [13,20].…”

Lipid Metabolism and Release of Cytochrome c from Mitochondria

“…For charged proteins and lipids, electrostatic interactions are usually dominant. Thus, utilizing liposome inhibition assays and reflection spectroscopy, it was shown that cytochrome c binds preferentially to monolayers of acidic phospholipids such phosphatidylserine, phosphatidylserine and cardiolipin (Demel, 1994;Demel et al, 1989;Kozarac et al, 1988). A comparison between apocytochrome c and holocytochrome c revealed striking differences in phospholipid specificities.…”