The specificity of peptidyl‐tRNA hydrolase from E. coli
The specificity of peptidyl‐tRNA hydrolase from E. coli
复制标题
大肠杆菌肽基-tRNA 水解酶的特异性
DOI：
10.1016/0014-5793(75)80700-9
复制
发表时间：
1975
期刊：
影响因子：
3.5
通讯作者：
N. de Groot
中科院分区：
文献类型：
--
作者：
J. Shiloach;Y. Lapidot;N. de Groot
肽基-tRNA 水解酶是一种水解肽或 N 封闭的氨酰残基与 tRNA 末端核糖的 2' 或 3'OH 基团之间的酯键的酶 [1]。从大肠杆菌中分离出的酶的特异性已经得到了一些详细的研究。该酶不会水解肽的甲酯或乙酯 [2]、肽的 2' 或 3' 腺苷酯或未封闭的氨酰基-t RNA [3]。该酶对某种 tRNA 不具有特异性，因为它能够水解所有经过测试的 N-封闭氨酰基-tRNA [4]，并攻击肽基-tRNA，例如 (Gly)*-phetRNAE。大肠杆菌和 (Gly),-phe-tRNAYeaSt 具有相同的效率 [6]。似乎只有一个例外，正如 Lapidot 等人[S] 发现的那样，该酶不会攻击（或仅非常轻微地攻击）大肠杆菌起始 tRNA 的肽酯，例如 (Gly),-mettRNAFef。最近，已经研究了 tRNA 在 3' 端腺苷或倒数第二个胞苷核苷酸中的修饰；其中一些 tRNA 可以被氨酰化。其中一种可以通过用高碘酸盐氧化 3’-末端核糖并用硼氢化钠将二醛还原为 tRNA-CCA 来制备，,,,,[7]。其他衍生物可以通过将 ATP 类似物掺入 tRNA-CC 或 CTP 类似物以及用 tRNA-核苷酸转移酶将 ATP 掺入 tRNA-C 来制备。在这项工作中，我们描述了纯化的大肠杆菌肽基-tRNA 水解酶对由这些物质制备的几种肽基-tRNA 的作用。
Peptidyl-tRNA hydrolase is an enzyme which hydrolyses the ester bond between a peptide or a N-blocked aminoacyl residue and the 2’or 3’OH group of the terminal ribose of tRNA [l]. The specificity of the enzyme isolated from E. coli has been studied in some detail. The enzyme does not hydrolyze methyl or ethyl esters of peptides [2], 2’or 3’adenosyl esters of peptides or unblocked aminoacyl-t RNA [3]. The enzyme is not specific for a certain tRNA since it is capable of hydrolysing all the N-blocked aminoacyl-tRNA’s tested [4] and attacks peptidyl-tRNA’s such as (Gly)*-phetRNAE. coli and (Gly),-phe-tRNAYeaSt with the same efficiency [6]. There seems to be only one exception as Lapidot et al.[S] found, that the enzyme does not attack (or attacks only very slightly) peptide esters of the E. coli initiator tRNA, such as (Gly),-mettRNAFefRecently, tRNA’s modified in the 3’-terminal adenosine or in the penultimate cytidine nucleotides have been investigated; some of these tRNA’s can be aminoacylated. One of these can be prepared by oxidizing the 3’-terminal ribose with periodate and reduction of the dialdehyde with sodium borhydride to tRNA-CCA,,,,,[7]. Other derivatives can be prepared by incorporating ATP analogues to tRNA-CC or CTP analogues and ATP to tRNA-C with the tRNA-nucleotidyl transferase. In this work we describe the action of a purified E. coli peptidyl-tRNA hydrolase on several peptidyl-tRNA’s prepared from these