Highly Specific and Efficient Cleavage of Squid tRNALys Catalyzed by Magnesium Ions(*)
Highly Specific and Efficient Cleavage of Squid tRNALys Catalyzed by Magnesium Ions(*)
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镁离子催化鱿鱼 tRNALys 的高度特异性和高效裂解 (*)
DOI：
10.1074/jbc.270.17.10097
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
N. Okada
中科院分区：
文献类型：
--
作者：
M. Matsuo;T. Yokogawa;K. Nishikawa;Kimitsuna Watanabe;N. Okada
从鱿鱼（Loligo bleekeri）中分离出分别对应于密码子 AAA 和 AAG 的两个赖氨酸同工受体 tRNA，并测定了它们的核苷酸序列。在分析过程中，我们发现带有反密码子 CUU 的 tRNA 在镁离子存在的情况下在特定位点被有效切割，而带有反密码子 UUU 的 tRNA 则不能。裂解几乎完全发生在 G15 和 D16(p16) 之间的磷酸二酯键上。该裂解反应最显着的特点是最终产物不是2',3'-环状磷酸酯，而是主要是3'-磷酸酯。因此，该反应不同于酵母 tRNAPheby 铅的充分表征的裂解以及由各种其他金属酶催化的反应。 60 位胞苷残基的存在是有效裂解所必需的，但对于反应而言并不重要，并且整个 tRNA 分子必须完整才能实现这种特异性且有效的裂解反应。本研究提供的证据表明，存在一种新的 tRNA 裂解催化机制，该机制利用生物上普遍存在的离子，而不是有毒的非必需离子（如铅）。
Two lysine isoacceptor tRNAs corresponding to the codons AAA and AAG, respectively, were isolated from squid (Loligo bleekeri), and their nucleotide sequences were determined. During this analysis, we discovered that the tRNA with the anticodon CUU was efficiently cleaved at a specific site in the presence of magnesium ions, whereas the tRNA with the anticodon UUU was not. Cleavage occurred almost exclusively at the phosphodiester linkage between G15and D16(p16). The most remarkable feature of this cleavage reaction is that the end product was not a 2′,3′-cyclic phosphate but was mainly a 3′-phosphate. Thus, this reaction was distinct from the well characterized cleavage of yeast tRNAPheby lead and from reactions catalyzed by various other metalloribozymes. The presence of a cytidine residue at position 60 was required for efficient cleavage but was not crucial for the reaction, and the entire tRNA molecule had to be intact for this specific and efficient cleavage reaction. The present study provides evidence that there exists a new catalytic mechanism for cleavage of tRNA that exploits biologically ubiquitous ions rather than toxic, nonessential ions such as lead.
酵母 tRNA(Phe) 片段的催化 RNA 反应。
影响因子：
2.9
作者：
Deng,HY;Termini,J
通讯作者：
Termini,J
两种 RNA 催化的 RNA 裂解反应的表征。
DOI：
10.1101/sqb.1987.052.01.032
发表时间：
1987
期刊：
Cold Spring Harbor symposia on quantitative biology
影响因子：
--
作者：
Sampson,JR;Sullivan,FX;Behlen,LS;DiRenzo,AB;Uhlenbeck,OC
通讯作者：
Uhlenbeck,OC