Microscopic versus macroscopic diffusion in model membranes by electron spin resonance spectral-spatial imaging.
Microscopic versus macroscopic diffusion in model membranes by electron spin resonance spectral-spatial imaging.
复制标题
通过电子自旋共振光谱空间成像在模型膜中进行微观与宏观扩散。
DOI：
10.1016/s0006-3495(91)82310-4
复制
发表时间：
1991
影响因子：
3.4
通讯作者：
Freed,JH
中科院分区：
文献类型：
--
作者：
Shin,YK;Ewert,U;Budil,DE;Freed,JH
本文利用光谱-空间电子自旋共振成像新技术，在同一样品中同时测定了磷脂自旋标记物（16-PC）在1-棕榈酰-2-油酰-sn-甘油-磷脂酰胆碱模型膜中的宏观和微观扩散系数。16-PC自旋标记物自扩散的宏观扩散系数Dmacro是通过将浓度分布成像为时间的函数而获得的，并且在22 ℃下它是（2.3 +/- 0.4）× 10（-8）cm 2/s。自旋探针的相对扩散的微观扩散系数Dmicro从谱线加宽随自旋标记物浓度的变化获得，这是由于自旋-自旋相互作用。对于相同条件下的相同样品，发现Dmicro显著大于Dmacro，并且估计为至少（1.0 +/-0.4）X 10（-7）cm 2/s。根据Dmicro使用的模型，简要讨论了它们之间差异的可能来源。
The macroscopic and the microscopic diffusion coefficients of a phospholipid spin label (16-PC) in the model membrane 1-palmitoyl-2-oleoyl-sn-glycero-phosphatidylcholine have been measured simultaneously in the same sample utilizing the new technique of spectral-spatial electron spin resonance imaging. The macroscopic diffusion coefficient Dmacro for self-diffusion of 16-PC spin label is obtained from imaging the concentration profiles as a function of time, and it is (2.3 +/- 0.4) x 10(-8) cm2/s at 22 degrees C. The microscopic diffusion coefficient Dmicro for relative diffusion of the spin probes is obtained from the variation of the spectral line broadening with spin label concentration, which is due to spin-spin interactions. Dmicro is found to be substantially greater than Dmacro for the same sample at the same conditions, and is estimated to be at least (1.0 +/- 0.4) x 10(-7) cm2/s. Possible sources for their difference are briefly discussed in terms of the models used for Dmicro.