Author/Editor		Kveder, M; Pifat, G; Pečar, S; Schara, M
Title		The ESR characterization of molecular mobility in the lipid surface layer of human serum lipoproteins
Type		članek
Source		Chem Phys Lipids
Vol. and No.		Letnik 70, št. 1
Publication year		1994
Volume		str. 101-8
Language		eng
Abstract		Three different nitroxides were used to probe either the head group (Tempil stearate) or acyl chain region (Spin labeled cholestane (ChSl) and methyl ester of 5 doxyl palmitate (MeFASL(10,3))) of human plasma low density lipoproteins (LDL) and very low density lipoproteins (VLDL). The ESR data were compared with the simulated spectra which assume rapid anisotropic motion of nitroxide. The results indicate that in the head group region of both LDL and VLDL only the slowing down of the rotational motion occurred when temperature was lowered and the whole region showed up as a unique compartment. On the other hand, the acyl chain region, probed with MeFASL(10,3), behaved as one compartment at physiological temperatures, while at lower temperatures coexistence of fluid and immobilized components were observed. The ESR spectra of lipoproteins labeled with Cholestane showed even higher sensitivity to the mobility constraints. Here, the LDL spectra revealed a drastic immobilization of ChSl axial rotation already at physiological temperatures. The results of these experiments were discussed in terms of core phase transition and/or lipid-protein interactions.
Descriptors		LIPOPROTEINS, LDL LIPOPROTEINS, VLDL ELECTRON SPIN RESONANCE SPECTROSCOPY LIPOPROTEINS, LDL LIPOPROTEINS, VLDL SPIN LABELS TEMPERATURE