title: Mg2+ dependence of 70 S ribosomal protein flexibility revealed by hydrogen/deuterium exchange and mass spectrometry.
abstract: The ribosome from Escherichia coli requires a specific concentration of Mg(2+) 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 Mg(2+) concentrations, using mass spectrometry. Many proteins exhibited a sigmoidal curve for Mg(2+) concentration dependence, incorporating more deuterium at lower Mg(2+) 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.
authors.affiliation: Biometal Science Laboratory, RIKEN SPring-8 Center, Harima Institute, 1-1-1 Kouto, Sayo, Hongo 679-5148, Japan. tyamamot@spring8.or.jp
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Shimizu
authors.forename: Takuya
authors.initials: T
authors.lastname: Ueda
authors.forename: Yoshitsugu
authors.initials: Y
authors.lastname: Shiro
mesh_terms: D041961:Deuterium Exchange Measurement; D004926:Escherichia coli / Q000737:chemistry* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism; D008274:Magnesium / Q000737:chemistry* / Q000378:metabolism; D013058:Mass Spectrometry; D012269:Ribosomal Proteins / Q000737:chemistry* / Q000378:metabolism; D012270:Ribosomes / Q000737:chemistry* / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: D029968:Escherichia coli Proteins; D012269:Ribosomal Proteins; D008274:Magnesium