Watanabe K, Oshima T, Nishimura S
Nucleic Acids Res. 1976 Jul;3(7):1703-13. doi: 10.1093/nar/3.7.1703.
5-Methyl-2-thiouridine (S) in tRNA-Met-f from an extreme thermophile is located in the TpsiC region, replacing T, and has a positive CD band centered at 310 nm. Upon heating, the profiles of the change in this band were similar to the UV melting profiles of the change monitored at 260 nm. This strongly suggests a close relation between heat denaturation of the tRNA and the conformation of the S base. Oligonucleotides containing S showed negative CD bands at 320-330 nm, like the monomer S itself, but when the 3'-2/5 fragment containing S formed a complex with the complementary 5'-3/5 fragment, a positive CD band appeared at 310 nm. These results suggest that combination of the TpsiC loop containing S with the hU loop is necessary for the positive band of S at 310 nm. S may serve to strengthen the association of the TpsiC loop with the hU loop in tRNA of the thermophile.
来自嗜热菌的tRNA-Met-f中的5-甲基-2-硫代尿苷(S)位于TψC区域,取代了T,并且在310nm处有一个正的圆二色带。加热时,该带变化的图谱与在260nm处监测的紫外熔解图谱相似。这强烈表明tRNA的热变性与S碱基的构象之间存在密切关系。含有S的寡核苷酸在320 - 330nm处显示负的圆二色带,就像单体S本身一样,但是当含有S的3'-2/5片段与互补的5'-3/5片段形成复合物时,在310nm处出现正的圆二色带。这些结果表明,含有S的TψC环与hU环结合对于S在310nm处的正带是必要的。S可能有助于加强嗜热菌tRNA中TψC环与hU环的结合。