Altman S
Nucleic Acids Res. 1976 Feb;3(2):441-8. doi: 10.1093/nar/3.2.441.
The anticodon of an ochre-suppressing derivative of E. coli tRNA I Tyr, previously identified as UUA, can contain a modified uridine (U+) in the first position. The novel modified nucleotide has been identified by two-dimensional thin layer chromatography following RNase T2 digestion of anticodon-containing fragments. Up+ is found in less than stoichiometric molar yields in preparations of tRNA I Tyr su + oc. The electrophoretic mobility of Up+ is the same as Up at pH 3.5 and pH 7.5. U+ probably does not contain sulfur since it cannot be labeled with 35S in vivo incorporation experiments.
大肠杆菌tRNA I Tyr的赭石抑制衍生物的反密码子先前被确定为UUA，其第一位可含有一个修饰的尿苷（U+）。通过对含反密码子片段进行RNase T2消化后，用二维薄层色谱法鉴定出了这种新型修饰核苷酸。在tRNA I Tyr su + oc制剂中，Up+的摩尔产率低于化学计量。在pH 3.5和pH 7.5条件下，Up+的电泳迁移率与Up相同。U+可能不含硫，因为在体内掺入实验中它不能被35S标记。
