Lees N D, Bard M, Kemple M D, Haak R A, Kleinhans F W
Biochim Biophys Acta. 1979 Jun 2;553(3):469-75. doi: 10.1016/0005-2736(79)90302-x.
ESR investigations designed to determine membrane order parameter in sterol mutants of Saccharomyces cerevisiae were conducted using the membrane probe, 5-doxyl stearic acid. These mutants are blocked in the ergosterol biosynthetic pathway and thus do not synthesize ergosterol, the end product sterol. They do not require exogenous ergosterol for growth and, therefore, incorporate ergosterol biosynthetic intermediates in their membrane. Increasing order parameter is reflective of an increase in membrane rigidity. Single mutants involving B-ring delta 8 leads to delta 7 isomerization (erg 2) and C-24 methylation (erg 6) showed greater membrane rigidity than wild-type during exponential growth. A double mutant containing both lesions (erg 6/2) showed an even greater degree of membrane rigidity. During stationary phase the order of decreasing membrane rigidity was erg 6 greater than erg 6/2 greater than erg 2 = wild-type. The increased membrane order parameter was attributed to the presence of substituted sterols rather than increased sterol content or altered fatty acid synthesis.
利用膜探针5-硬脂酸氧基硬脂酸对酿酒酵母甾醇突变体进行了旨在确定膜序参数的红细胞沉降率（ESR）研究。这些突变体在麦角固醇生物合成途径中受阻，因此不合成麦角固醇（终产物甾醇）。它们生长不需要外源性麦角固醇，因此在其膜中掺入麦角固醇生物合成中间体。序参数增加反映膜刚性增加。涉及B环δ8至δ7异构化（erg2）和C-24甲基化（erg6）的单突变体在指数生长期间显示出比野生型更大的膜刚性。含有两种损伤的双突变体（erg6/2）显示出更高程度的膜刚性。在稳定期，膜刚性降低的顺序为erg6大于erg6/2大于erg2 =野生型。膜序参数增加归因于取代甾醇的存在，而非甾醇含量增加或脂肪酸合成改变。
