Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany.
Martin-Luther-Universität Halle-Wittenberg, Institut für Biologie, Weinbergweg 10, 06120 Halle (Saale), Germany.
Structure. 2015 Jan 6;23(1):149-160. doi: 10.1016/j.str.2014.11.008. Epub 2014 Dec 24.
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 Å 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.
由乳酸克鲁维酵母杀伤毒素不敏感基因 KTI11/DPH3 编码的小而高度保守的 Kti11 别名 Dph3 蛋白参与真核延伸因子 2 的二氢尿嘧啶修饰，以及与 Kti13 一起参与延伸因子依赖性 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。我们分别以 2.4 和 2.9 Å 的分辨率解决了酿酒酵母 Kti13 和 Kti11/Kti13 异二聚体的晶体结构，并通过体外和体内突变分析验证了相互作用的残基。我们表明，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将 Kti13 鉴定为二氢尿嘧啶修饰途径的另一个组成部分，并深入了解允许 Kti11/Kti13 异二聚体共同调节核糖体蛋白合成中两个连续步骤的分子机制。
