Effects of freezing on membranes and proteins in LNCaP prostate tumor cells.
Effects of freezing on membranes and proteins in LNCaP prostate tumor cells.
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冷冻对 LNCaP 前列腺肿瘤细胞膜和蛋白质的影响。
DOI：
10.1016/j.bbamem.2006.12.007
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
Bischof,JohnC
中科院分区：
文献类型：
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作者：
Wolkers,WillemF;Balasubramanian,SaravanaK;Ongstad,EmilyL;Zec,HelenaC;Bischof,JohnC
傅里叶变换红外光谱（FTIR）和冷冻显微镜被用来定义在LNCaP前列腺肿瘤细胞冷冻过程中的细胞损伤的过程中，在分子水平上。在以2 °C/min冷却的过程中监测细胞团块，同时冰成核温度在-3 ° C和-10 °C之间变化。我们表明，细胞倾向于在成核后急剧下降，除非细胞内的冰形成发生。预测的细胞内冰形成的发生率在低于-4 °C的冰成核温度下迅速增加，细胞存活在-6 °C的成核温度下表现出最佳状态。冰核温度对细胞的膜相行为有很大的影响。液晶凝胶相变的发生与冰成核温度相一致。此外，与在-10 °C成核的样品相比，在-3 °C成核导致了更加合作的相变，并且伴随着在冷冻状态下膜的残留构象紊乱更低。这些观察结果被解释成核温度对细胞脱水和细胞内冰形成的程度的影响。酰胺-III条带分析显示，蛋白质在冷冻过程中相对稳定，并且热诱导的蛋白质变性与α-螺旋结构的突然减少和β-折叠结构的伴随增加一致，起始温度约为48 °C。
Fourier transform infrared spectroscopy (FTIR) and cryomicroscopy were used to define the process of cellular injury during freezing in LNCaP prostate tumor cells, at the molecular level. Cell pellets were monitored during cooling at 2 °C/min while the ice nucleation temperature was varied between −3 and −10 °C. We show that the cells tend to dehydrate precipitously after nucleation unless intracellular ice formation occurs. The predicted incidence of intracellular ice formation rapidly increases at ice nucleation temperatures below −4 °C and cell survival exhibits an optimum at a nucleation temperature of −6 °C. The ice nucleation temperature was found to have a great effect on the membrane phase behavior of the cells. The onset of the liquid crystalline to gel phase transition coincided with the ice nucleation temperature. In addition, nucleation at −3 °C resulted in a much more co-operative phase transition and a concomitantly lower residual conformational disorder of the membranes in the frozen state compared to samples that nucleated at −10 °C. These observations were explained by the effect of the nucleation temperature on the extent of cellular dehydration and intracellular ice formation. Amide-III band analysis revealed that proteins are relatively stable during freezing and that heat-induced protein denaturation coincides with an abrupt decrease in α-helical structures and a concomitant increase in β-sheet structures starting at an onset temperature of approximately 48 °C.