Pleiotropic effects of intron removal on base modification pattern of yeast tRNA(Phe): An in vitro study
Pleiotropic effects of intron removal on base modification pattern of yeast tRNA(Phe): An in vitro study
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DOI：
10.1093/nar/25.14.2694
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发表时间：
1997-07-15
影响因子：
14.9
通讯作者：
Grosjean, H
中科院分区：
文献类型：
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作者：
Jiang, HQ;Motorin, Y;Grosjean, H
无细胞酵母提取物已成功用于催化酵母 tRNA(Phe)（反密码子 GAA）中 14 种天然存在的修饰核苷酸中的 II 的酶促形成。它们是 m(2)G(10)、D-17、m(2)(2)G(26)、Cm-32、Gm(34)、psi(39)、m(5)C(40)、m(7)G(46)、m(5)C(49)、T-54 和 psi(55)。在体外条件下只有D-16、Y-37和m(1)A(58)没有形成，但是定量产生了m(1)G(37)而不是Y-37。天然存在的内含子对于m(5)C(40) 的形成是绝对必需的，同时它完全阻碍Cm-32、Gm(34) 和m(1)G(37) 的酶促形成。 m(2)(2)G(26)、psi(39)、m(7)G(46)、m(5)C(49)、T-54 和 psi(55) 的酶促形成不受内含子存在的影响或仅轻微影响。这些结果使我们能够将不同的 tRNA 修饰酶分为三组：内含子不敏感、内含子依赖性和需要内含子不存在的酶。由反密码子茎和环组成并用 19 个核苷酸长的内含子延长的截短 tRNA(Phe) 是 tRNA: 胞嘧啶 40 甲基化酶的底物，这一事实表明该酶不仅严格依赖于内含子，而且不需要完全结构化的 tRNA。
Cell-free yeast extract has been successfully used to catalyze the enzymatic formation of II out of the 14 naturally occurring modified nucleotides in yeast tRNA(Phe) (anticodon GAA). They are m(2)G(10), D-17, m(2)(2)G(26), Cm-32, Gm(34), psi(39), m(5)C(40), m(7)G(46), m(5)C(49), T-54 and psi(55). Only D-16, Y-37 and m(1)A(58) were not formed under in vitro conditions, However, m(1)G(37) was quantitatively produced instead of Y-37. The naturally occurring intron was absolutely required for m(5)C(40) formation while it hindered completely the enzymatic formation of Cm-32, Gm(34) and m(1)G(37). Enzymatic formation of m(2)(2)G(26), psi(39), m(7)G(46), m(5)C(49), T-54 and psi(55) Were not or only slightly affected by the presence of the intron, These results allow us to classify the different tRNA modification enzymes into three groups: intron insensitive, intron dependent, and those requiring the absence of the intron. The fact that truncated tRNA(Phe) consisting of the anticodon stem and loop prolonged with the 19 nucleotide long intron is a substrate for tRNA: cytosine-40 methylase demonstrates that the enzyme is not only strictly intron dependent, but also does not require fully structured tRNA.