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Phosphorylation of elongation factor Tu prevents ternary complex formation

Item Type:Article
Title:Phosphorylation of elongation factor Tu prevents ternary complex formation
Creators Name:Alexander, C. and Bilgin, N. and Lindschau, C. and Mesters, J.R. and Kraal, B. and Hilgenfeld, R. and Erdmann, V.A. and Lippmann, C.
Abstract:The elongation factor Tu (EF-Tu) is a member of the GTP/GDP-binding proteins and interacts with various partners during the elongation cycle of protein biosynthesis thereby mediating the correct binding of amino-acylated transfer RNA (aa-tRNA) to the acceptor site (A-site) of the ribosome. After GTP hydrolysis EF-Tu is released in its GDP-bound state. In vivo, EF-Tu is post-translationally modified by phosphorylation. Here we report that the phosphorylation of EF-Tu by a ribosome associated kinase activity is drastically enhanced by EF-Ts. The antibiotic kirromycin, known to block EF-Tu function, inhibits the modification. This effect is specific, since kirromycin-resistant mutants do become phosphorylated in the presence of the antibiotic. On the other hand, phosphorylated wild-type EF-Tu does not bind kirromycin. Most interestingly, the phosphorylation of EF-Tu abolishes its ability to bind aa-tRNA. In the GTP conformation the site of modification is located at the interface between domains 1 and 3 and is involved in a strong interdomain hydrogen bond. Introduction of a charged phosphate group at this position will change the interaction between the domains, leading to an opening of the molecule reminiscent of the GDP conformation. A model for the function of EF-Tu phosphorylation in protein biosynthesis is presented.
Keywords:Anti-Bacterial Agents, Computer Graphics, Escherichia Coli, Molecular Models, Peptide Elongation Factor Tu, Phosphorylation, Protein Conformation, Post-Protein Processing, Pyridones, Amino Acyl Transfer RNA
Source:Journal of Biological Chemistry
Publisher:American Society for Biochemistry and Molecular Biology
Page Range:14541-14547
Date:16 June 1995
Official Publication:https://doi.org/10.1074/jbc.270.24.14541
PubMed:View item in PubMed

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