Directional transition from initiation to elongation in bacterial translation

The transition of the 30S initiation complex (IC) to the translating 70S ribosome after 50S subunit joining provides an important checkpoint for mRNA selection during translation in bacteria. Here, we study the timing and control of reactions that occur during 70S IC formation by rapid kinetic techn...

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Main Authors:	Goyal, Akanksha, Belardinelli, Riccardo, Maracci, Cristina, Milón, Pohl, Rodnina, Marina V.
Format:	Online
Language:	English
Published:	Oxford University Press 2015
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4678851/

id	pubmed-4678851
recordtype	oai_dc
spelling	pubmed-46788512015-12-16 Directional transition from initiation to elongation in bacterial translation Goyal, Akanksha Belardinelli, Riccardo Maracci, Cristina Milón, Pohl Rodnina, Marina V. Gene regulation, Chromatin and Epigenetics The transition of the 30S initiation complex (IC) to the translating 70S ribosome after 50S subunit joining provides an important checkpoint for mRNA selection during translation in bacteria. Here, we study the timing and control of reactions that occur during 70S IC formation by rapid kinetic techniques, using a toolbox of fluorescence-labeled translation components. We present a kinetic model based on global fitting of time courses obtained with eight different reporters at increasing concentrations of 50S subunits. IF1 and IF3 together affect the kinetics of subunit joining, but do not alter the elemental rates of subsequent steps of 70S IC maturation. After 50S subunit joining, IF2-dependent reactions take place independent of the presence of IF1 or IF3. GTP hydrolysis triggers the efficient dissociation of fMet-tRNAfMet from IF2 and promotes the dissociation of IF2 and IF1 from the 70S IC, but does not affect IF3. The presence of non-hydrolyzable GTP analogs shifts the equilibrium towards a stable 70S–mRNA–IF1–IF2–fMet-tRNAfMet complex. Our kinetic analysis reveals the molecular choreography of the late stages in translation initiation. Oxford University Press 2015-12-15 2015-09-03 /pmc/articles/PMC4678851/ /pubmed/26338773 http://dx.doi.org/10.1093/nar/gkv869 Text en © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research. http://creativecommons.org/licenses/by-nc/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Goyal, Akanksha Belardinelli, Riccardo Maracci, Cristina Milón, Pohl Rodnina, Marina V.
spellingShingle	Goyal, Akanksha Belardinelli, Riccardo Maracci, Cristina Milón, Pohl Rodnina, Marina V. Directional transition from initiation to elongation in bacterial translation
author_facet	Goyal, Akanksha Belardinelli, Riccardo Maracci, Cristina Milón, Pohl Rodnina, Marina V.
author_sort	Goyal, Akanksha
title	Directional transition from initiation to elongation in bacterial translation
title_short	Directional transition from initiation to elongation in bacterial translation
title_full	Directional transition from initiation to elongation in bacterial translation
title_fullStr	Directional transition from initiation to elongation in bacterial translation
title_full_unstemmed	Directional transition from initiation to elongation in bacterial translation
title_sort	directional transition from initiation to elongation in bacterial translation
description	The transition of the 30S initiation complex (IC) to the translating 70S ribosome after 50S subunit joining provides an important checkpoint for mRNA selection during translation in bacteria. Here, we study the timing and control of reactions that occur during 70S IC formation by rapid kinetic techniques, using a toolbox of fluorescence-labeled translation components. We present a kinetic model based on global fitting of time courses obtained with eight different reporters at increasing concentrations of 50S subunits. IF1 and IF3 together affect the kinetics of subunit joining, but do not alter the elemental rates of subsequent steps of 70S IC maturation. After 50S subunit joining, IF2-dependent reactions take place independent of the presence of IF1 or IF3. GTP hydrolysis triggers the efficient dissociation of fMet-tRNAfMet from IF2 and promotes the dissociation of IF2 and IF1 from the 70S IC, but does not affect IF3. The presence of non-hydrolyzable GTP analogs shifts the equilibrium towards a stable 70S–mRNA–IF1–IF2–fMet-tRNAfMet complex. Our kinetic analysis reveals the molecular choreography of the late stages in translation initiation.
publisher	Oxford University Press
publishDate	2015
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4678851/
_version_	1613512898821226496

Directional transition from initiation to elongation in bacterial translation

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