Structure of the Elongator cofactor complex Kti11/Kti13 provides insight into the role of Kti13 in Elongator-dependent tRNA modification - Archive ouverte HAL
Journal Articles FEBS Journal Year : 2015

Structure of the Elongator cofactor complex Kti11/Kti13 provides insight into the role of Kti13 in Elongator-dependent tRNA modification

Abstract

Modification of wobble uridines of many eukaryotic tRNAs requires the Elongator complex, a highly conserved six-subunit eukaryotic protein assembly, as well as the Killer toxin-insensitive (Kti) proteins 11-14. Kti11 was additionally shown to be implicated in the biosynthesis of diphthamide, a post-translationally modified histidine of translation elongation factor 2. Recent data indicate that iron-bearing Kti11 functions as an electron donor to the [4Fe-4S] cluster of radical S-Adenosylmethionine enzymes, triggering the subsequent radical reaction. We show here that recombinant yeast Kti11 forms a stable 1 : 1 complex with Kti13. To obtain insights into the function of this heterodimer, the Kti11/Kti13 complex was purified to homogeneity, crystallized, and its structure determined at 1.45 A resolution. The importance of several residues mediating complex formation was confirmed by mutagenesis. Kti13 adopts a fold characteristic of RCC1-like proteins. The seven-bladed beta-propeller consists of a unique mixture of four- and three-stranded blades. In the complex, Kti13 orients Kti11 and restricts access to its electron-carrying iron atom, constraining the electron transfer capacity of Kti11. Based on these findings, we propose a role for Kti13, and discuss the possible functional implications of complex formation. DATABASE: Structural data have been submitted to the Protein Data Bank under accession number 4X33.

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Dates and versions

hal-02179589 , version 1 (10-07-2019)

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Olga Kolaj-Robin, A Mcewen, Jean Cavarelli, Bertrand Séraphin. Structure of the Elongator cofactor complex Kti11/Kti13 provides insight into the role of Kti13 in Elongator-dependent tRNA modification. FEBS Journal, 2015, 282 (5), pp.819-833. ⟨10.1111/febs.13199⟩. ⟨hal-02179589⟩
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