Kleinhans F W, Lees N D, Bard M, Haak R A, Woods R A
Chem Phys Lipids. 1979 Jan-Feb;23(2):143-54. doi: 10.1016/0009-3084(79)90042-2.
Yeast sterol mutants were subjected to ESR analysis in an attempt to elucidate how altered sterol composition correlates with membrane permeability. The technique requires spin labeling the intact yeast cells with a small, water-soluble nitroxide probe (2,2,5,5 tetramethyl-3-pyrrolin-1-oxyl-3-carboxylic acid, PCA), suspending cells in a NiCl2 solution, and measuring the extent of Ni2+ entry through the membrane by its magnetic dipolar line broadening effect on the PCA signal. The wild type, A184D, was found to be impermeable to Ni2+ during all growth phases while the sterol mutant erg 6/2 was readily permeable to Ni2+. Other sources of line broadening such as increased rotational correlation time and cell nonviability are shown to be neglibible. Internal Ni2+ concentrations for erg 6/2 and kinetics of Ni2+ entry were determined.
对酵母甾醇突变体进行了电子自旋共振（ESR）分析，以试图阐明甾醇组成的改变如何与膜通透性相关。该技术需要用一种小的水溶性氮氧化物探针（2,2,5,5-四甲基-3-吡咯啉-1-氧基-3-羧酸，PCA）对完整的酵母细胞进行自旋标记，将细胞悬浮在氯化镍溶液中，并通过其对PCA信号的磁偶极线展宽效应来测量镍离子通过膜的进入程度。发现野生型A184D在所有生长阶段对镍离子均不可渗透，而甾醇突变体erg 6/2对镍离子则很容易渗透。其他导致线展宽的来源，如旋转相关时间增加和细胞无活力，被证明可以忽略不计。测定了erg 6/2的内部镍离子浓度和镍离子进入的动力学。
