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Journal Article

Timing of GTP binding and hydrolysis by translation termination factor RF3.

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

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Kuhlenkötter,  S.
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;

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Wintermeyer,  W.
Research Group of Ribosome Dynamics, MPI for biophysical chemistry, Max Planck Society;

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1854610.pdf
(Publisher version), 574KB

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Citation

Peske, F., Kuhlenkötter, S., Rodnina, M. V., & Wintermeyer, W. (2014). Timing of GTP binding and hydrolysis by translation termination factor RF3. Nucleic Acids Research, 42(3), 1812-1820. doi:10.1093/nar/gkt1095.


Cite as: http://hdl.handle.net/11858/00-001M-0000-0014-A588-D
Abstract
Protein synthesis in bacteria is terminated by release factors 1 or 2 (RF1/2), which, on recognition of a stop codon in the decoding site on the ribosome, promote the hydrolytic release of the polypeptide from the transfer RNA (tRNA). Subsequently, the dissociation of RF1/2 is accelerated by RF3, a guanosine triphosphatase (GTPase) that hydrolyzes GTP during the process. Here we show that—in contrast to a previous report—RF3 binds GTP and guanosine diphosphate (GDP) with comparable affinities. Furthermore, we find that RF3–GTP binds to the ribosome and hydrolyzes GTP independent of whether the P site contains peptidyl-tRNA (pre-termination state) or deacylated tRNA (post-termination state). RF3–GDP in either pre- or post-termination complexes readily exchanges GDP for GTP, and the exchange is accelerated when RF2 is present on the ribosome. Peptide release results in the stabilization of the RF3–GTP–ribosome complex, presumably due to the formation of the hybrid/rotated state of the ribosome, thereby promoting the dissociation of RF1/2. GTP hydrolysis by RF3 is virtually independent of the functional state of the ribosome and the presence of RF2, suggesting that RF3 acts as an unregulated ribosome-activated switch governed by its internal GTPase clock.