Structure of the Kti11/Kti13 Heterodimer and Its Double Role in Modifications of tRNA and Eukaryotic Elongation Factor 2
Structure of the Kti11/Kti13 Heterodimer and Its Double Role in Modifications of tRNA and Eukaryotic Elongation Factor 2
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DOI：
10.1016/j.str.2014.11.008
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发表时间：
2015-01-06
期刊：
影响因子：
5.7
通讯作者：
Mueller, Christoph W.
中科院分区：
文献类型：
--
作者：
Glatt, Sebastian;Zabel, Rene;Mueller, Christoph W.
Kti11 / Dph3编码的小而高度保守的Kti11 alias Dph3蛋白参与真核生物伸长因子2的双苯二胺修饰，并与Kti13一起参与伸长依赖tRNA摆动碱基修饰，从而通过两种不同的机制影响蛋白质生物合成的速度和准确性。我们分别在2.4埃和2.9埃分辨率下解析了酿酒酵母Kti13和Kti11/Kti13异源二聚体的晶体结构，并通过体外和体内突变分析验证了相互作用残基。我们发现Kti11的金属配位及其与Kti13的异二聚化对于这两种翻译控制机制都是必不可少的。我们的结构和功能分析确定Kti13是二苯二胺修饰途径的一个额外组成部分，并提供了允许Kti11/Kti13异源二聚体共同调节核糖体蛋白合成两个连续步骤的分子机制。
The small, highly conserved Kti11 alias Dph3 protein encoded by the Kluyveromyces lactis killer toxin insensitive gene KTI11/DPH3 is involved in the diphthamide modification of eukaryotic elongation factor 2 and, together with Kti13, in Elongator-dependent tRNA wobble base modifications, thereby affecting the speed and accuracy of protein biosynthesis through two distinct mechanisms. We have solved the crystal structures of Saccharomyces cerevisiae Kti13 and the Kti11/Kti13 heterodimer at 2.4 and 2.9 angstrom resolution, respectively, and validated interacting residues through mutational analysis in vitro and in vivo. We show that metal coordination by Kti11 and its heterodimerization with Kti13 are essential for both translational control mechanisms. Our structural and functional analyses identify Kti13 as an additional component of the diphthamide modification pathway and provide insight into the molecular mechanisms that allow the Kti11/Kti13 heterodimer to coregulate two consecutive steps in ribosomal protein synthesis.