NMR-based molecular ruler for determining the depth of intercalants within the lipid bilayer. Part V: a comparison of liposomes, bioliposomes and erythrocyte ghosts.

Afri et al. (2014a,b) have recently reported their mapping of DMPC liposomes using (13)C NMR in conjunction with a wide range of difunctional intercalants: n-ketoesters, n-ketoacids and n-ketophosphatidylcholines. The present study initiates a comparable study of bioliposomes and erythrocyte ghosts.

NMR-based molecular ruler for determining the depth of intercalants within the lipid bilayer: Part III: studies on keto esters and acids.

The development of "molecular rulers" would allow one to quantitatively locate the penetration depth of intercalants within lipid bilayers. To this end, an attempt was made to correlate the (13)C NMR chemical shift of polarizable "reporter" carbons (e.g.

NMR-based molecular ruler for determining the depth of intercalants within the lipid bilayer. Part IV: studies on ketophospholipids.

In our companion paper, we described the preparation and intercalation of two homologous series of dicarbonyl compounds, methyl n-oxooctadecanoates and the corresponding n-oxooctadecanoic acids (n=4-16), into DMPC liposomes. (13)C NMR chemical shift of the various carbonyls was analyzed using an E(T)(30) solvent polarity-chemical shift correlation table and the corresponding calculated penetration depth (in Å). An iterative best fit analysis of the data points revealed an exponential correlation between E(T)(30) micropolarity and the penetration depth (in Å) into the liposomal bilayer.

Using fluorescence to locate intercalants within the lipid bilayer of liposomes, bioliposomes and erythrocyte ghosts.

In previous work, we have shown the utility of the "NMR technique" in locating intercalants within the lipid bilayer. We describe herein the development of a more sensitive and complementary "fluorescence technique" for this purpose and its application to liposomes, bioliposomes and erythrocyte ghosts. This technique is based on the observation in selected compounds of an excellent correlation between the emission wavelength (λ(em)) and Dimroth-Reichardt E(T)(30) polarity parameter for the solvent in which the fluorescence emission spectrum was obtained.