Pilz I, Malnig F, Kratky O, Von der Haar F
Eur J Biochem. 1977 May 2;75(1):35-41. doi: 10.1111/j.1432-1033.1977.tb11501.x.
The scattered X-ray intensities from dilute solutions of tRNASer (yeast) in 0.1 M Soerensen buffer at pH 7.0 were measured at 25 degrees C. The radius of gyration, molecular weight and volume were determined. A model equivalent in scattering is given. The change of the conformation of tRNASer by heating was followed by small-angle X-ray measurements and ultraviolet absorption in a temperature range 20-70 degrees C. The molecule begins to unfold at about 40 degrees C and 70 degrees C has a random coil conformation. Addition of magnesium stabilizes the tRNASer molecule. The reversibility of the melting process was also studied by both methods. An interesting effect was found by ultraviolet absorption: by heating the tRNASer solutions to 55 degrees C and 60 degrees C and subsequently slowly cooling, the melting curves lie at higher absorption values than the corresponding cooling curves. The small-angle data and optical properties of tRNASer are compared with those of tRNAPhe which has already been thoroughly investigated.
在25摄氏度下测量了0.1M索伦森缓冲液（pH 7.0）中稀酵母丝氨酸转运核糖核酸（tRNASer）溶液的散射X射线强度。测定了回转半径、分子量和体积。给出了一个在散射方面等效的模型。通过小角X射线测量和在20至70摄氏度温度范围内的紫外吸收跟踪了加热时tRNASer构象的变化。该分子在约40摄氏度时开始展开，在70摄氏度时具有无规卷曲构象。镁的加入使tRNASer分子稳定。还通过这两种方法研究了熔解过程的可逆性。通过紫外吸收发现了一个有趣的效应：将tRNASer溶液加热到55摄氏度和60摄氏度，随后缓慢冷却，熔解曲线的吸收值高于相应的冷却曲线。将tRNASer的小角数据和光学性质与已经被充分研究的苯丙氨酸转运核糖核酸（tRNAPhe）的进行了比较。
