Fourier transform infrared spectroscopic identification of gel phase domains in reconstituted phospholipid vesicles containing Ca2+-ATPase.
Fourier transform infrared spectroscopic identification of gel phase domains in reconstituted phospholipid vesicles containing Ca2+-ATPase.
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傅里叶变换红外光谱鉴定含有 Ca2-ATP 酶的重构磷脂囊泡中的凝胶相域。
DOI：
10.1016/0005-2736(86)90546-8
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Mendelsohn,R
中科院分区：
文献类型：
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作者：
Jaworsky,M;Mendelsohn,R
从兔肌浆网中分离、纯化Ca ~（2+）-ATP酶，并将其重组到含有主要成分1，2-二油酰磷脂酰胆碱（DEPC）和酰基链全氘代1，2-二肉豆蔻酰磷脂酰胆碱（DMPC-d_（54））的脂质环境中。差示扫描量热法（DSC）已被用来阐明这种脂质对的相行为，而傅里叶变换红外光谱（FT-IR）已被用来监测蛋白质存在下的每个脂质组分的状态。脂质混合物在至少大部分组成范围内显示出凝胶状态可溶解性，这一结果雅阁货车Dijck等人（Biochim. Biophys. Acta 470，58-69（1977）），对于具有蛋白化DMPC的二元混合物。因此，酰基链全氘代不会大大改变脂质对的可溶解性。Ca 2 +-ATP酶与这种脂质对的重建以中等效率进行。取决于脂质组成，高达80%的内源性脂质可被替代。注意到不寻常的组合物依赖性蛋白质诱导的影响，对脂质熔化特性。与相同组成的二元脂质混合物相比，在低水平的DMPC-d54下，DEPC和DMPC-d54组分的熔融过程均变宽并向较低温度移动。这表明蛋白质以类似的方式干扰两种脂质。在高水平的DMPC-d54下，DEPC组分在接近纯DEPC的温度下表现出高度协同的熔融过程。这强烈表明DEPC结构域存在于双层中（至少在低温下），并且Ca 2 +-ATP酶被排除在这些结构域之外。因此，该蛋白质表现出优先与DMPC-d54组分的相互作用。这项工作证明了实用的FT-IR识别的分子来源的特定结构域在合理复杂的脂质混合物。这项工作的相关性，天然膜系统的脂质结构域已被观察到的几个小组进行了讨论。
Ca2+-ATPase from rabbit sarcoplasmic reticulum has been isolated, purified, and reconstituted into lipid environments containing as primary components 1,2-dielaidoylphosphatidylcholine (DEPC) and acyl-chain perdeuterated 1,2-dimyristoylphosphatidylcholine (DMPC-d54). Differential scanning calorimetry (DSC) has been used to elucidate the phase behavior of this lipid pair while Fourier transform infrared spectroscopy (FT-IR) has been used to monitor the state of each lipid component in the presence of protein. The lipid mixture shows gel state miscibility over at least most of the composition range, a result in good accord with Van Dijck et al. (Biochim. Biophys. Acta 470, 58–69 (1977)), for the binary mixture with proteated DMPC. Acyl chain perdeuteration thus does not greatly alter the miscibility properties of the lipid pair. Reconstitution of Ca2+-ATPase with this lipid pair proceeds with moderate efficiency. Up to 80% of the endogenous lipid can be replaced depending on the lipid composition. Unusual composition-dependent protein-induced effects on lipid melting properties are noticed. At low levels of DMPC-d54, both the DEPC and DMPC-d54components have their melting processes broadened and shifted to lower temperatures, compared with binary lipid mixtures of the same composition. This suggests that protein perturbs both lipids in similar fashion. At high levels of DMPC-d54, the DEPC component exhibits a highly cooperative melting process at temperatures close to that for pure DEPC. This strongly indicates that domains of DEPC are present (at least at low temperatures) in the bilayer, and that Ca2+-ATPase is excluded from these domains. The protein thus exhibits preferential interaction with the DMPC-d54component. This work demonstrates the utility of FT-IR for identification of the molecular origin of particular domains in reasonably complex lipid mixtures. The relevance of this work to native membrane systems where lipid domains have been observed by several groups is discussed.