Interaction of cytochrome P-450 with phospholipids in dimyristoylphosphatidylcholine and dimyristoylphosphatidylglycerol mixtures
Gurinovich, N.A.; Lunevich, A.I.; Strizhakova, E.P.; Kiselev, P.A.
Molekuliarnaia Biologiia 21(6): 1525-1533
1987
ISSN/ISBN: 0026-8984 PMID: 2833688 Document Number: 299608
ESR and microcalorimetry methods were employed to investigate the thermotropic properties and structure of proteoliposomes that incorporate cytochrome P450 and DMPC-DMPG binary mixtures depending on cytochrome P450 content and phospholipid composition. The microcalorimetry data demonstrated that the incorporation of cytochrome P450 into the phospholipid mixture resulted in bilayer thermal stabilization. The maximum shift of the temperature and proteoliposome transition enthalpy were achieved at the protein/lipid molar ratio of 1:1000 in almost equimolar phospholipid mixture. Using fatty acids that were spin-labeled at different positions (C5, C12, C16), it has been shown that the incorporation of cytochrome P450 into lipid mixtures containing 0-100% DMPG decreases C12 and C16 mobility and increases the C5 order parameter at transition phase (30 degrees C) and liquid crystal phase (37 degrees C) of bilayer. The maximum alteration amplitude of the probes used was not characteristic for the separate DMPC and DMPG but rather for the mixture at the molar ratio close to equimolar value. It is proposed that cytochrome P450 incorporation into the binary mixture initiated the formation of the bilayer crystal-like phase.