Slow motions in oriented phospholipid bilayers and effects of cholesterol or gramicidin. A 19F-NMR T1 rho study.
Slow motions in oriented phospholipid bilayers and effects of cholesterol or gramicidin. A 19F-NMR T1 rho study.
复制标题
定向磷脂双层的慢动作以及胆固醇或短杆菌肽的影响。
DOI：
10.1016/s0006-3495(89)82734-1
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发表时间：
1989
影响因子：
3.4
通讯作者：
Ho,C
中科院分区：
文献类型：
--
作者：
Peng,ZY;Tjandra,N;Simplaceanu,V;Ho,C
在我们早期工作的扩展中（Peng，Z.- y.，辛普莱西亚努岛J. Lowe和C.何1988. Biophys. J. 54：81-95），双标架核自旋晶格弛豫（T1 rho）技术已用于研究在不存在和存在胆固醇或短杆菌肽作为膜相互作用分子的情况下由质子化或全氘代19 F标记的磷脂制备的脂质双层中的慢分子运动（10（-4）-10（-6）s）。由先前观察到的19 F-1H交叉极化引起的并发症可以通过在酰基链中用2 H取代1H来消除。对于具有全氘代酰基链的磷脂分子，仅发现T-1（1 rho）对锁定场强度的弱依赖性，这表明在5 x 10（-6）和4 x 10（-5）s之间不存在具有单个明确定义的相关时间的慢运动。然而，T-1（1 ρ）的取向依赖性可以很好地拟合的运动模型，无论是一个慢动作具有未指定的几何形状，或与两个特定类型的慢动作的叠加。胆固醇和短杆菌肽在改变磷脂双层中慢动作的几何形状或权重方面显示出明显的效果，如取向依赖性的变化所反映的。这两种添加剂也表现出完全不同的标记位置特异性。将讨论胆固醇和短杆菌肽对磷脂双层动力学的诱导作用的定性理解。
In an extension of our earlier work (Peng, Z.-y., V. Simplaceanu, I. J. Lowe, and C. Ho. 1988. Biophys. J. 54:81–95), the rotating-frame nuclear spin-lattice relaxation (T1 rho) technique has been used to investigate the slow molecular motions (10(-4) - 10(-6) s) in lipid bilayers prepared from protonated or perdeuterated 19F-labeled phospholipids in the absence and presence of cholesterol or gramicidin as membrane-interacting molecules. Complications caused by the 19F-1H cross-polarization observed previously can be removed by the substitution of 2H for 1H in the acyl chains. Only a weak dependence of the T-1(1 rho) on the locking field strength is found for a phospholipid molecule with perdeuterated acyl chains, indicating that there are no slow motions with a single, well-defined correlation time between 5 x 10(-6) and 4 x 10(-5) s. However, the orientation dependences of the T-1(1 rho) can be well fitted by motional models with either one slow motion having an unspecified geometry or with a superposition of two specific types of slow motions. Cholesterol and gramicidin show distinct effects in altering either the geometry or the weighting of slow motions in phospholipid bilayers, as reflected by changes in the orientation dependence. These two additives also exhibit quite different label-position specificities. A qualitative understanding of the induced effects of cholesterol and gramicidin on the dynamics of phospholipid bilayers will be discussed.