Covalent enzyme-RNA complex: a tRNA modification that prevents a covalent enzyme interaction also prevents aminoacylation.
Covalent enzyme-RNA complex: a tRNA modification that prevents a covalent enzyme interaction also prevents aminoacylation.
复制标题
共价酶-RNA 复合物：阻止共价酶相互作用的 tRNA 修饰也可以阻止氨酰化。
DOI：
10.1073/pnas.82.2.339
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发表时间：
1985
影响因子：
11.1
通讯作者：
Schimmel,P
中科院分区：
文献类型：
--
作者：
Starzyk,R;Schoemaker,H;Schimmel,P
先前的研究表明，氨基酰基trna合成酶通过Michael在尿苷8的碳-6位置上添加亲核酶，与同源trna形成瞬时共价加合物。我们报道了大肠杆菌酪氨酸tRNA中4-硫脲在8位的5,6双键的选择性还原，以防止推定的共价酶-核酸加合物的形成。完全还原的tRNA分子因氨基酰化而失活。通过部分还原，产生了活性和非活性分子的混合池，失活的程度与4-硫脲还原的程度完全匹配。从这个混合池中回收的活性分子在第8位保持不变。结果与共价酶- rna加合物是该tRNA氨基酰化的必需中间体的观点一致。
Previous work indicates that aminoacyl-tRNA synthetases make a transient covalent adduct with cognate tRNAs, through Michael addition of an enzyme nucleophile to the carbon-6 position of uridine 8. We report the selective reduction of the 5,6 double bond of 4-thiouridine at position 8 in Escherichia coli tyrosine tRNA, so as to prevent formation of the presumed covalent enzyme-nucleic acid adduct. The completely reduced tRNA molecules are inactivated for aminoacylation. With partial reduction, a mixed pool of active and inactive molecules is created and the degree of inactivation exactly matches the extent of 4-thiouridine reduction. The active molecules recovered from this mixed pool are specifically unaltered at position 8. The results are consistent with the view that the covalent enzyme-RNA adduct is an obligatory intermediate for aminoacylation of this tRNA.