The tRNA recognition mechanism of the minimalist SPOUT methyltransferase, TrmL.
The tRNA recognition mechanism of the minimalist SPOUT methyltransferase, TrmL.
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极简SPOUT甲基转移酶TrmL的tRNA识别机制
DOI：
10.1093/nar/gkt568
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发表时间：
2013-09
影响因子：
14.9
通讯作者：
Wang ED
中科院分区：
文献类型：
--
作者：
Liu RJ;Zhou M;Fang ZP;Wang M;Zhou XL;Wang ED
与来自SPOUT甲基转移酶超家族的其他转移rna （tRNA）修饰酶不同，tRNA （Um34/Cm34）甲基转移酶TrmL缺乏tRNA结合的通常扩展结构域，仅由SPOUT结构域组成。该酶的催化和tRNA识别机制尚不清楚。通过使用从删除TrmL基因的大肠杆菌菌株纯化的trna，我们发现TrmL可以独立催化s -腺苷- l-蛋氨酸到和异受体的甲基转移，而不需要其他trna结合蛋白的参与。我们已经解决了载脂蛋白TrmL的晶体结构和与s -腺苷-同型半胱氨酸的复合物，并确定了辅因子结合位点和一个可能的活性位点。测定TrmL突变体的甲基转移酶活性和tRNA结合亲和力，以鉴定TrmL结合tRNA的重要残基。我们的研究结果表明，TrmL作为一种同源二聚体，通过使用SPOUT结构域的保守的c端一半进行催化，而来自另一个亚基的不太保守的n端一半的残基参与tRNA识别。
Unlike other transfer RNAs (tRNA)-modifying enzymes from the SPOUT methyltransferase superfamily, the tRNA (Um34/Cm34) methyltransferase TrmL lacks the usual extension domain for tRNA binding and consists only of a SPOUT domain. Both the catalytic and tRNA recognition mechanisms of this enzyme remain elusive. By using tRNAs purified from an Escherichia coli strain with the TrmL gene deleted, we found that TrmL can independently catalyze the methyl transfer from S-adenosyl-L-methionine to and isoacceptors without the involvement of other tRNA-binding proteins. We have solved the crystal structures of TrmL in apo form and in complex with S-adenosyl-homocysteine and identified the cofactor binding site and a possible active site. Methyltransferase activity and tRNA-binding affinity of TrmL mutants were measured to identify residues important for tRNA binding of TrmL. Our results suggest that TrmL functions as a homodimer by using the conserved C-terminal half of the SPOUT domain for catalysis, whereas residues from the less-conserved N-terminal half of the other subunit participate in tRNA recognition.
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影响因子：
5.3
作者：
Chen P;Jäger G;Zheng B
通讯作者：
Zheng B
DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
大肠杆菌K-12的构造框架，单基因敲除突变体：Keio Collection。
影响因子：
9.9
作者：
通讯作者：
--
影响因子：
2.9
作者：
Brulé, H;Elliott, M;Holmes, WM
通讯作者：
Holmes, WM
影响因子：
4.5
作者：
Benitez-Paez, Alfonso;Villarroya, Magda;Armengod, M-Eugenia
通讯作者：
Armengod, M-Eugenia