Sprinzl M, Sternbach H, von der Haar F, Cramer F
Eur J Biochem. 1977 Dec;81(3):579-89. doi: 10.1111/j.1432-1033.1977.tb11985.x.
Structural analogues of adenosine 5'-triphosphate and cytidine 5'-triphosphate were investigated as substrates for ATP(CTP):tRNA nucleotidyl transferase. Eight out of 26 ATP analogues and six out of nine CTP analogues were incorporated into the 3' terminus of tRNA. In general, for the recognition of the substrates the modification of the cytidine is less critical than is the modification of adenosine. An isosteric substitution on the ribose residue is possible in both CTP and ATP. The free hydroxyls of these triphosphates can be replaced by an amino group or hydrogen atom without loss of substrate properties. Modifications of positions 1, 2, 6, and 8 on the adenine ring of ATP are not allowed whereas modification on positions 2, 4 and 5 on the cytosine ring of CTP are tolerated by the enzyme. No differences can be observed in the substrate properties of ATP(CTP):tRNA nucleotidyl transferase isolated from different sources. Methods for preparation of tRNA species, which are shortened at their 3' end by one or more nucleotides, and analytical procedures for characterisation of these modified tRNAs are described.
研究了腺苷5'-三磷酸（ATP）和胞苷5'-三磷酸（CTP）的结构类似物作为ATP(CTP):tRNA核苷酸转移酶的底物。26种ATP类似物中有8种、9种CTP类似物中有6种被掺入到tRNA的3'末端。一般来说，对于底物的识别，胞苷的修饰不如腺苷的修饰关键。在CTP和ATP中，核糖残基上都可以进行等排取代。这些三磷酸酯的游离羟基可以被氨基或氢原子取代而不丧失底物性质。ATP腺嘌呤环上1、2、6和8位的修饰是不允许的，而CTP胞嘧啶环上2、4和5位的修饰则能被该酶耐受。从不同来源分离得到的ATP(CTP):tRNA核苷酸转移酶的底物性质没有差异。描述了制备3'末端缩短了一个或多个核苷酸的tRNA种类的方法，以及表征这些修饰tRNA的分析程序。
