Five steps in the conversion of a large precursor RNA into bacteriophage proline and serine transfer RNAs.
Five steps in the conversion of a large precursor RNA into bacteriophage proline and serine transfer RNAs.
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将大前体 RNA 转化为噬菌体脯氨酸和丝氨酸转移 RNA 的五个步骤。
DOI：
10.1016/s0022-2836(75)80182-3
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发表时间：
1975
影响因子：
5.6
通讯作者：
W. McClain
中科院分区：
文献类型：
--
作者：
J. Seidman;B. Barrell;W. McClain
我们描述了前体RNA的核苷酸序列衍生到噬菌体T4脯氨酸和丝氨酸转移RNA。前体RNA有限消化获得的大寡核苷酸片段确定了前体RNA内的排列为5 ‘ -脯氨酸trna -丝氨酸tRNA-3 ’。转移rna的核苷酸序列也在附录中给出了脯氨酸tRNA和McClainet al.（1975）的随附论文中给出了丝氨酸tRNA。核苷酸序列的比较表明，前体RNA缺乏两种转移RNA的3 ' ccaoh残基，表明这些残基必须在前体RNA成熟过程中通过酶的方式添加。噬菌体T2脯氨酸和丝氨酸trna的前体RNA在核苷酸序列上与T4前体RNA几乎相同。唯一的区别是在3 '端，丝氨酸tRNA的ccaoh残基存在于T2前体RNA中，并且被认为是在转录过程中合成的。我们已经描述了前体RNA转化为脯氨酸和丝氨酸trna的酶促步骤。这些研究依赖于不完全成熟的前体RNA的核苷酸序列测定，这些前体RNA积聚在大肠杆菌细胞中，缺乏与前体RNA成熟相关的酶。结合以往和目前的研究结果，我们提出了以下途径的转移rna的出现。该过程是通过外切酶和tRNA核苷酸转移酶的联合作用将ccaoh添加到T4前体RNA的3 '端而启动的。这两种酶都来自宿主。由这些反应产生的T4前体RNA中间体与T2前体RNA相同。终止于ccao2的T2和T4前体RNA随后被宿主酶核糖核酸酶P切割两次，产生两个转移RNA大小的产物，其中包含转移RNA物种的5 '端。裂解产物源自前体RNA的3 '端，终止于CCAOHis丝氨酸tRNA；在这个转移RNA物种上添加一个2 ' - o -甲基代表了丝氨酸tRNA生物合成的最后一步。第二个核糖核酸酶P切割产物是一种不成熟的脯氨酸tRNA，缺乏其3 ' ccaoh残基。脯氨酸tRNA通过外切酶和tRNA核苷酸转移酶的共同作用形成。
We describe the nucleotide sequence derivation of the precursor RNA to bacteriophage T4 proline and serine transfer RNAs. Large oligonucleotide fragments obtained by limited digestion of the precursor RNA define the arrangement within the precursor RNA as 5′-proline tRNA-serine tRNA-3′. The nucleotide sequences of the transfer RNAs are also derived, in the Appendix for proline tRNA and in the accompanying paper by McClainet al.(1975) for serine tRNA. Comparisons of nucleotide sequences show that the precursor RNA lacks 3′ CCAOHresidues of both transfer RNA species, indicating that these residues must be added enzymatically during precursor RNA maturation. The precursor RNA to bacteriophage T2 proline and serine tRNAs is nearly identical in nucleotide sequence to the T4 precursor RNA. The only difference is at the 3′ terminus where the CCAOHresidues of serine tRNA are present in the T2 precursor RNA and are believed to be synthesized during transcription.We have characterized the enzymatic steps involved in the conversion of precursor RNA into proline and serine tRNAs. The studies rely on nucleotide sequence determinations of incompletely matured precursor RNAs that accumulate inEscherichia colicells deficient in the enzymes associated with precursor RNA maturation. The combined results of previous and present studies permit us to propose the following pathway for the appearance of the transfer RNAs. The process is initiated by the addition of CCAOHto the 3′ terminus of the T4 precursor RNA through the combined action of an exonuclease and tRNA nucleotidyltransferase. Both enzymes are of host origin. The T4 precursor RNA intermediate generated by these reactions is identical to the T2 precursor RNA. T2 and T4 precursor RNAs terminating in CCAOHare then cleaved twice by the host enzyme ribonuclease P to yield two transfer RNA-size products that contain the 5′ termini of the transfer RNA species. The cleavage product derived from the 3′ end of the precursor RNA and terminating in CCAOHis serine tRNA; addition of a 2′-O-methyl group to this transfer RNA species represents the terminal step in the biosynthesis of serine tRNA. The second ribonuclease P cleavage product is a species of immature proline tRNA that lacks its 3′ CCAOHresidues. Proline tRNA is then formed by the combined action of the exonuclease and tRNA nucleotidyltransferase.