Mg2+ Dependence of 70 S Ribosomal Protein Flexibility Revealed by Hydrogen/Deuterium Exchange and Mass Spectrometry |
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| Authors: | Tatsuya Yamamoto Yoshihiro Shimizu Takuya Ueda Yoshitsugu Shiro |
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| Affiliation: | From the ‡Biometal Science Laboratory, RIKEN SPring-8 Center, Harima Institute, 1-1-1 Kouto, Sayo, Hongo 679-5148 and ;the §Department of Medical Genome Science, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5, Kashiwanoha, Chiba 277-8562, Japan |
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| Abstract: | The ribosome from Escherichia coli requires a specific concentration of Mg2+ to maintain the 70 S complex formation and allow protein synthesis, and then the structure must be stable and flexible. How does the ribosome acquire these conflicting factors at the same time? Here, we investigated the hydrogen/deuterium exchange of 52 proteins in the 70 S ribosome, which controlled stability and flexibility under various Mg2+ concentrations, using mass spectrometry. Many proteins exhibited a sigmoidal curve for Mg2+ concentration dependence, incorporating more deuterium at lower Mg2+ concentration. By comparing deuterium incorporation with assembly, we have discovered a typical mechanism of complexes for acquiring both stability and flexibility at the same time. In addition, we got information of the localization of flexibility in ribosomal function by the analysis of related proteins with stalk protein, tRNA, mRNA, and nascent peptide, and demonstrate the relationship between structure, assembly, flexibility, and function of the ribosome. |
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| Keywords: | Methods/Isotope Exchange Methods/Mass Spectrometry Protein/RNA Interactions Protein/Stability RNA/Ribosome Assembly RNA/Ribosome Function Mg2+ Dependence Flexibility |
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