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Activities of the peptidyl transferase center of ribosomes lacking protein L27
The ribosome is the molecular machine responsible for protein synthesis in all living organisms. Its catalytic core, the peptidyl transferase center (PTC), is built of rRNA, although several proteins reach close to the inner rRNA shell. In the Escherichia coli ribosome, the flexible N-terminal tail...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Cold Spring Harbor Laboratory Press
2015
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4647459/ https://www.ncbi.nlm.nih.gov/pubmed/26475831 http://dx.doi.org/10.1261/rna.053330.115 |
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author | Maracci, Cristina Wohlgemuth, Ingo Rodnina, Marina V. |
author_facet | Maracci, Cristina Wohlgemuth, Ingo Rodnina, Marina V. |
author_sort | Maracci, Cristina |
collection | PubMed |
description | The ribosome is the molecular machine responsible for protein synthesis in all living organisms. Its catalytic core, the peptidyl transferase center (PTC), is built of rRNA, although several proteins reach close to the inner rRNA shell. In the Escherichia coli ribosome, the flexible N-terminal tail of the ribosomal protein L27 contacts the A- and P-site tRNA. Based on computer simulations of the PTC and on previous biochemical evidence, the N-terminal α-amino group of L27 was suggested to take part in the peptidyl-transfer reaction. However, the contribution of this group to catalysis has not been tested experimentally. Here we investigate the role of L27 in peptide-bond formation using fast kinetics approaches. We show that the rate of peptide-bond formation at physiological pH, both with aminoacyl-tRNA or with the substrate analog puromycin, is independent of the presence of L27; furthermore, translation of natural mRNAs is only marginally affected in the absence of L27. The pH dependence of the puromycin reaction is unaltered in the absence of L27, indicating that the N-terminal α-amine is not the ionizing group taking part in catalysis. Likewise, L27 is not required for the peptidyl-tRNA hydrolysis during termination. Thus, apart from the known effect on subunit association, which most likely explains the phenotype of the deletion strains, L27 does not appear to be a key player in the core mechanism of peptide-bond formation on the ribosome. |
format | Online Article Text |
id | pubmed-4647459 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2015 |
publisher | Cold Spring Harbor Laboratory Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-46474592015-12-01 Activities of the peptidyl transferase center of ribosomes lacking protein L27 Maracci, Cristina Wohlgemuth, Ingo Rodnina, Marina V. RNA Report The ribosome is the molecular machine responsible for protein synthesis in all living organisms. Its catalytic core, the peptidyl transferase center (PTC), is built of rRNA, although several proteins reach close to the inner rRNA shell. In the Escherichia coli ribosome, the flexible N-terminal tail of the ribosomal protein L27 contacts the A- and P-site tRNA. Based on computer simulations of the PTC and on previous biochemical evidence, the N-terminal α-amino group of L27 was suggested to take part in the peptidyl-transfer reaction. However, the contribution of this group to catalysis has not been tested experimentally. Here we investigate the role of L27 in peptide-bond formation using fast kinetics approaches. We show that the rate of peptide-bond formation at physiological pH, both with aminoacyl-tRNA or with the substrate analog puromycin, is independent of the presence of L27; furthermore, translation of natural mRNAs is only marginally affected in the absence of L27. The pH dependence of the puromycin reaction is unaltered in the absence of L27, indicating that the N-terminal α-amine is not the ionizing group taking part in catalysis. Likewise, L27 is not required for the peptidyl-tRNA hydrolysis during termination. Thus, apart from the known effect on subunit association, which most likely explains the phenotype of the deletion strains, L27 does not appear to be a key player in the core mechanism of peptide-bond formation on the ribosome. Cold Spring Harbor Laboratory Press 2015-12 /pmc/articles/PMC4647459/ /pubmed/26475831 http://dx.doi.org/10.1261/rna.053330.115 Text en © 2015 Maracci et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society http://creativecommons.org/licenses/by/4.0/ This article, published in RNA, is available under a Creative Commons License (Attribution 4.0 International), as described at http://creativecommons.org/licenses/by/4.0/. |
spellingShingle | Report Maracci, Cristina Wohlgemuth, Ingo Rodnina, Marina V. Activities of the peptidyl transferase center of ribosomes lacking protein L27 |
title | Activities of the peptidyl transferase center of ribosomes lacking protein L27 |
title_full | Activities of the peptidyl transferase center of ribosomes lacking protein L27 |
title_fullStr | Activities of the peptidyl transferase center of ribosomes lacking protein L27 |
title_full_unstemmed | Activities of the peptidyl transferase center of ribosomes lacking protein L27 |
title_short | Activities of the peptidyl transferase center of ribosomes lacking protein L27 |
title_sort | activities of the peptidyl transferase center of ribosomes lacking protein l27 |
topic | Report |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4647459/ https://www.ncbi.nlm.nih.gov/pubmed/26475831 http://dx.doi.org/10.1261/rna.053330.115 |
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