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Journal Article

Ribosome-induced tuning of GTP hydrolysis by a translational GTPase.

MPS-Authors
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Maracci,  C.
Department of Physical Biochemistry, MPI for biophysical chemistry, Max Planck Society;

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Peske,  F.
Department of Physical Biochemistry, MPI for biophysical chemistry, Max Planck Society;

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Pohl,  C.
Department of Physical Biochemistry, MPI for biophysical chemistry, Max Planck Society;

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Rodnina,  M. V.
Department of Physical Biochemistry, MPI for biophysical chemistry, Max Planck Society;

External Ressource
Fulltext (public)

2060834.pdf
(Publisher version), 939KB

Supplementary Material (public)

2060834_Suppl.pdf
(Supplementary material), 86KB

Citation

Maracci, C., Peske, F., Dannies, E., Pohl, C., & Rodnina, M. V. (2014). Ribosome-induced tuning of GTP hydrolysis by a translational GTPase. Proceedings of the National Academy of Sciences of the United States of America, 111(40), 14418-14423. doi: 10.1073/pnas.1412676111.


Cite as: http://hdl.handle.net/11858/00-001M-0000-0023-EE46-0
Abstract
GTP hydrolysis by elongation factor Tu (EF-Tu), a translational GTPase that delivers aminoacyl-tRNAs to the ribosome, plays a crucial role in decoding and translational fidelity. The basic reaction mechanism and the way the ribosome contributes to catalysis are a matter of debate. Here we use mutational analysis in combination with measurements of rate/pH profiles, kinetic solvent isotope effects, and ion dependence of GTP hydrolysis by EF-Tu off and on the ribosome to dissect the reaction mechanism. Our data suggest that—contrary to current models—the reaction in free EF-Tu follows a pathway that does not involve the critical residue H84 in the switch II region. Binding to the ribosome without a cognate codon in the A site has little effect on the GTPase mechanism. In contrast, upon cognate codon recognition, the ribosome induces a rearrangement of EF-Tu that renders GTP hydrolysis sensitive to mutations of Asp21 and His84 and insensitive to K+ ions. We suggest that Asp21 and His84 provide a network of interactions that stabilize the positions of the γ-phosphate and the nucleophilic water, respectively, and thus play an indirect catalytic role in the GTPase mechanism on the ribosome.