Gurinovich N A, Lunevich A Ia, Strizhakova E P, Kiselev P A
Mol Biol (Mosk). 1987 Nov-Dec;21(6):1525-33.
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.
采用血沉棕黄层（ESR）和微量量热法研究了包含细胞色素P450以及取决于细胞色素P450含量和磷脂组成的二肉豆蔻酰磷脂酰胆碱-二肉豆蔻酰磷脂酰甘油（DMPC-DMPG）二元混合物的蛋白脂质体的热致性质和结构。微量量热数据表明，将细胞色素P450掺入磷脂混合物中会导致双层热稳定性增强。在几乎等摩尔的磷脂混合物中，当蛋白质/脂质摩尔比为1:1000时，温度和蛋白脂质体转变焓的最大变化得以实现。使用在不同位置（C5、C12、C16）进行自旋标记的脂肪酸，结果表明，将细胞色素P450掺入含有0 - 100% DMPG的脂质混合物中，会降低C12和C16的流动性，并增加双层在转变相（30℃）和液晶相（37℃）时C5的序参数。所用探针的最大变化幅度并非单独的DMPC和DMPG所特有，而是接近等摩尔值摩尔比的混合物所特有。有人提出，将细胞色素P450掺入二元混合物中会引发双层类晶相的形成。
