Guéron M, Shulman R G
Proc Natl Acad Sci U S A. 1975 Sep;72(9):3482-5. doi: 10.1073/pnas.72.9.3482.
We have observed well-resolved 31P resonances at 65 kG (109 MHz) in solutions of Escherichia coli tRNAGlu and yeast tRNAPhe. One resolved resonance, identified as the terminal phosphate, titrates with a pK = 6.35. Upon melting the yeast tRNAPhe in 0.1 M NaCl, without Mg++, the resolved peaks broaden and disappear in the vicinity of 35 degrees while the central cluster narrows drastically, shifts slightly, and loses its structure. Addition of Mg++ shifts one resolved peak and changes the shape of the cluster. The 31P lines are broader when observed at 65 kG than at 24 kG. The broadening is shown to come from chemical shift anisotropy which is estimated to be about 140 ppm.
我们在大肠杆菌tRNAGlu和酵母tRNAPhe的溶液中,于65 kG(109 MHz)处观察到了分辨率良好的31P共振。一个分辨出的共振峰,被鉴定为末端磷酸基团,其滴定的pK值为6.35。在0.1 M NaCl中、无Mg++的情况下将酵母tRNAPhe熔化时,分辨出的峰在35摄氏度附近变宽并消失,而中心簇则急剧变窄、略有移动并失去其结构。添加Mg++会使一个分辨出的峰发生移动,并改变簇的形状。在65 kG处观察到的31P谱线比在24 kG处更宽。这种展宽被证明是由化学位移各向异性引起的,估计约为140 ppm。