Conserved discrimination against misacylated tRNAs by two mesophilic elongation factor Tu orthologs.
Conserved discrimination against misacylated tRNAs by two mesophilic elongation factor Tu orthologs.
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DOI：
10.1021/bi800369q
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发表时间：
2008-07-22
期刊：
影响因子：
2.9
通讯作者：
Hendrickson, Tamara L.
中科院分区：
文献类型：
--
作者：
Cathopoulis, Terry J. T.;Chuawong, Pitak;Hendrickson, Tamara L.
延伸因子Tu(EF-Tu)与核糖体结合并装载延伸氨基酰转移RNA(AA-tRNAs)，用于蛋白质的生物合成。许多细菌通过间接的两步途径生物合成Gln-tRNAGln和Asn-tRNAAsn，该途径依赖于错酰化的tRNAs Glu-tRNAGln和Asp-tRNAAsn作为必需的中间产物。以前的热力学和实验分析已经证明Thermus thermophilus EF-Tu不结合Asp-tRNAAsn，并预测了对Glu-tRNAGln的类似歧视性反应[Asahara，H.和Uhlenbeck，O.(2005)，BioChemical 46,6194-6200和Roy，H.et al.(2007)核酸研究35,3420-3430]。通过识别这些错酰化的tRNA，EF-Tu在防止天冬酰胺和谷氨酰胺密码子的蛋白质中错误结合天冬氨酸和谷氨酸方面发挥了直接作用。在这里，我们报告了两个不同的中温EF-Tu同源物的特征，一个来自大肠杆菌，一种不利用Glu-tRNAGln或Asp-tRNAAsn的细菌，另一种来自幽门螺杆菌，一种生物体，两个错酰化的tRNA都是必不可少的。两个EF-Tu同源基因都歧视这些错酰化的tRNAs，证实了Glu-tRNAGln和Asp-tRNAAsn不会与EF-Tu形成复合体的预测。这些结果还表明，EF-Tu对这两种氨基酰-tRNA的区分能力是保守的，即使在像大肠杆菌这样的细菌中也不产生这两种错酰化的tRNA。
Elongation Factor Tu (EF-Tu) binds and loads elongating aminoacyl-transfer RNAs (aa-tRNAs) onto the ribosome for protein biosynthesis. Many bacteria biosynthesize Gln-tRNAGln and Asn-tRNAAsn by an indirect, two-step pathway that relies on the misacylated tRNAs Glu-tRNAGln and Asp-tRNAAsn as essential intermediates. Previous thermodynamic and experimental analyses have demonstrated that Thermus thermophilus EF-Tu does not bind Asp-tRNAAsn and predicted a similar discriminatory response against Glu-tRNAGln [Asahara, H. and Uhlenbeck, O., (2005), Biochemistry 46, 6194–6200 and Roy, H. et al. (2007) Nucleic Acids Research 35, 3420–3430]. By discriminating against these misacylated tRNAS, EF-Tu plays a direct role in preventing misincorporation of aspartate and glutamate into proteins at asparagine and glutamine codons. Here we report the characterization of two different mesophilic EF-Tu orthologs, one from Escherichia coli, a bacterium that does not utilize either Glu-tRNAGln or Asp-tRNAAsn, and the second from Helicobacter pylori, an organism in which both misacylated tRNAs are essential. Both EF-Tu orthologs discriminate against these misacylated tRNAs, confirming the prediction that Glu-tRNAGln, like Asp-tRNAAsn, will not form a complex with EF-Tu. These results also demonstrate that the capacity of EF-Tu to discriminate against both of these aminoacyl-tRNAs is conserved even in bacteria like E. coli that do not generate either misacylated tRNA.
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影响因子：
2.9
作者：
LOUIE, A;JURNAK, F
通讯作者：
JURNAK, F
影响因子：
3.2
作者：
LAPOINTE, J;DUPLAIN, L;PROULX, M
通讯作者：
PROULX, M
影响因子：
3.5
作者：
Núñez, HN;Lefimil, C;Orellana, O
通讯作者：
Orellana, O
影响因子：
5.6
作者：
Pleiss, JA;Uhlenbeck, OC
通讯作者：
Uhlenbeck, OC
DOI：
10.1016/j.bbapap.2004.02.015
发表时间：
2004-06-01
影响因子：
3.2
作者：
Hunter, SE;Spremulli, LL
通讯作者：
Spremulli, LL