关于酵母异亮氨酸转运核糖核酸（tRNAIle）和酵母丝氨酸转运核糖核酸（tRNASer）热稳定性的量热研究。

Calorimetric investigations on thermal stability of tRNAIle (yeast) and tRNASer (yeast).

作者信息

Filimonov V V, Privalov P L, Hinz H J, von der Haar F, Cramer F

出版信息

Eur J Biochem. 1976 Nov 1;70(1):25-31. doi: 10.1111/j.1432-1033.1976.tb10951.x.

DOI:10.1111/j.1432-1033.1976.tb10951.x

Abstract

Variation with temperature of the partial heat capacities of tRNAIle (yeast) and tRNASer (yeast) has been determined in two buffers at various salt conditions by scanning microcalorimetry. The overall molar transition enthalpy, deltaHt = 320 +/- 20 kcal mol-1 (1339 +/- 84 kJ mol-1) is identical for the two tRNA species within the limits of experimental error. deltaHt does not show any dependence on the nature of the buffer, nor does it vary on addition of 1 mM MgCl2 or 150 mM NaCl. Thermal unfolding of the native structure to the random coil cannot adequately be described by a two-state, concerted transition under the experimental conditions applied in this study, but exhibits a multistep mechanism characterized by sequential unfolding of separable cooperative domains.

摘要

通过扫描量热法，已在不同盐条件下的两种缓冲液中测定了酵母异亮氨酸转运核糖核酸（tRNAIle）和酵母丝氨酸转运核糖核酸（tRNASer）的部分热容随温度的变化。在实验误差范围内，两种tRNA物种的总摩尔转变焓ΔHt = 320±20千卡/摩尔（1339±84千焦/摩尔）是相同的。ΔHt既不显示对缓冲液性质的任何依赖性，在添加1 mM氯化镁或150 mM氯化钠时也没有变化。在本研究应用的实验条件下，天然结构向无规卷曲的热解折叠不能通过两态协同转变来充分描述，而是表现出一种多步机制，其特征是可分离的协同结构域依次解折叠。