Okabe N, Suyari K, Tomita K
J Biochem. 1975 Jun;77(6):1335-40.
The effects of temperature and guanidine hydrochloride (GuHC1) on the fluorescence polarization of Y base in partially purified yeast phenylalanine tRNA (p.p.tRNAPhe) and in acriflavine conjugates of crude yeast tRNA were investigated to elucidate the stability of the conformation at the 3'-CpCpA terminus and the anticodon loop of tRNA. The results can be summarized as follows: (1) The kinetic unit of the internal rotational motion near Y base in the anticodon loop of p.p.tRNAPhe seems to be independent of the temperature over the range 5--60degrees. Accelerated depolarization is observed in the 3'-CpCpA terminus at temperatures over 30degrees. This suggests that a change occurs in the native conformation of the 3'-CpCpA-acriflavine terminus at temperatures over 30degrees. (2) The fluorescence polarization of Y base in p.p.t-RNAPhe is not affected by the addition of GuHC1 up to 6 M, while that of acriflavine conjugated to the 3'-CpCpA terminus decreases markedly in the presence of 0.8 M GuHC1 reflecting the disruption of the native conformation. These results indicate that the local conformation near Y base is stable, but that of the amino acid acceptor terminus is not.
研究了温度和盐酸胍（GuHCl）对部分纯化的酵母苯丙氨酸tRNA（p.p.tRNAPhe）以及粗酵母tRNA的吖啶黄缀合物中Y碱基荧光偏振的影响，以阐明tRNA 3'-CpCpA末端和反密码子环处构象的稳定性。结果可总结如下：（1）p.p.tRNAPhe反密码子环中Y碱基附近内部旋转运动的动力学单元在5-60摄氏度范围内似乎与温度无关。在30摄氏度以上的温度下，在3'-CpCpA末端观察到去极化加速。这表明在30摄氏度以上的温度下，3'-CpCpA-吖啶黄末端的天然构象发生了变化。（2）在高达6 M的GuHCl存在下，p.p.t-RNAPhe中Y碱基的荧光偏振不受影响，而与3'-CpCpA末端缀合的吖啶黄在0.8 M GuHCl存在下荧光偏振明显降低，这反映了天然构象的破坏。这些结果表明，Y碱基附近的局部构象是稳定的，但氨基酸接受末端的构象不稳定。
