精胺对某些tRNA熔融曲线和熔融温度的影响

Effect of spermine on the melting curve and melting temperature(Tm) of some tRNAs

应用纯化的牛肝ｔＲＮＡＩｌｅ和酵母ｔＲＮＡＰｈｅ观察精胺对ｔＲＮＡ熔融曲线和熔融温度的影响。结果显示：在２ｍｍｏｌ／Ｌ精胺存在下，ｔＲＮＡ的吸光度（Ａｂｓ）随温度上升而下降，呈现“低色效应（ｈｙｐｏｃｈｒｏｍｉｓｍ）”和“反Ｔｍ（ｒｅｖｅｒｓｅＴｍ）”现象。本文认为精胺可与ｔＲＮＡ结合，遮掩ｔＲＮＡ分子对２６０ｎｍ紫外光的吸收，保护ｔＲＮＡ分子二级结构。实验亦观察了Ｍｇ２＋＋和Ｋ＋对ｔＲＮＡ熔融曲线和熔融温度的影响。

Using purified bovine liver tRNAIle and yeast tRNAIle, we studied the effects of spermine on the melt-ing curve and melting temperature(Tm )of the tRNAs. The results showed the absorbance at 260nm oftRNAs decreases with the increase of temperature in the presence of 2mmol/L spermine. We called thisphenomenon hypochromism and reverse-Tm of the tRNAs. It is suggested that spermine binds to tRNAsand stabilizes the secondary structure of the tRNAs.