Dahlquist F W, Muchmore D C, Davis J H, Bloom M
Proc Natl Acad Sci U S A. 1977 Dec;74(12):5435-9. doi: 10.1073/pnas.74.12.5435.
The deuterium magnetic resonance spectra of lipid-protein particles containing cytochrome c oxidase (ferrocytochrome c:oxygen oxidoreductase, EC 1.9.3.1) isolated from beef heart mitochondria and the specifically deuterated lipid 1-(16,16,16-trideuteropalmitoyl)-2-palmitoleoyl phosphatidylcholine are presented. These reconstituted particles are of uniform lipid and protein content; however, the spectra clearly show two environments characterized by distinctly different residual quadrupolar splittings or order parameters. The less-ordered environment shows a splitting similar to but slightly less than that of the pure lipid alone at a given temperature. The more restricted environment appears to be induced by the presence of the protein. The amount of the restricted lipid is clearly temperature dependent with a 2- to 3-fold decrease in relative amount from 2 to 22 degrees. The rate of exchange of lipid between the free and restricted environments is slower than 10(3)/sec. The significance of these phenomena is discussed.
本文展示了从牛心线粒体中分离出的含有细胞色素c氧化酶(亚铁细胞色素c:氧氧化还原酶,EC 1.9.3.1)的脂蛋白颗粒以及特定氘代脂质1-(16,16,16-三氘代棕榈酰基)-2-棕榈油酰磷脂酰胆碱的氘磁共振光谱。这些重构颗粒具有均匀的脂质和蛋白质含量;然而,光谱清楚地显示出两种环境,其特征是具有明显不同的残余四极分裂或序参数。在给定温度下,无序程度较低的环境显示出的分裂与单独的纯脂质相似,但略小。限制程度较高的环境似乎是由蛋白质的存在诱导的。受限脂质的量明显依赖于温度,相对量从2℃到22℃下降2至3倍。脂质在自由和受限环境之间的交换速率慢于10³/秒。讨论了这些现象的意义。