ジャーナル: Nucleic Acids Res / 年: 2016 タイトル: YphC and YsxC GTPases assist the maturation of the central protuberance, GTPase associated region and functional core of the 50S ribosomal subunit. 著者: Xiaodan Ni / Joseph H Davis / Nikhil Jain / Aida Razi / Samir Benlekbir / Andrew G McArthur / John L Rubinstein / Robert A Britton / James R Williamson / Joaquin Ortega / 要旨: YphC and YsxC are GTPases in Bacillus subtilis that facilitate the assembly of the 50S ribosomal subunit, however their roles in this process are still uncharacterized. To explore their function, we ...YphC and YsxC are GTPases in Bacillus subtilis that facilitate the assembly of the 50S ribosomal subunit, however their roles in this process are still uncharacterized. To explore their function, we used strains in which the only copy of the yphC or ysxC genes were under the control of an inducible promoter. Under depletion conditions, they accumulated incomplete ribosomal subunits that we named 45SYphC and 44.5SYsxC particles. Quantitative mass spectrometry analysis and the 5-6 Å resolution cryo-EM maps of the 45SYphC and 44.5SYsxC particles revealed that the two GTPases participate in the maturation of the central protuberance, GTPase associated region and key RNA helices in the A, P and E functional sites of the 50S subunit. We observed that YphC and YsxC bind specifically to the two immature particles, suggesting that they represent either on-pathway intermediates or that their structure has not significantly diverged from that of the actual substrate. These results describe the nature of these immature particles, a widely used tool to study the assembly process of the ribosome. They also provide the first insights into the function of YphC and YsxC in 50S subunit assembly and are consistent with this process occurring through multiple parallel pathways, as it has been described for the 30S subunit.
全体 : Assembly intermediate of the 50S ribosomal subunit, Class II
全体
名称: Assembly intermediate of the 50S ribosomal subunit, Class II
要素
複合体: Assembly intermediate of the 50S ribosomal subunit, Class II
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超分子 #1: Assembly intermediate of the 50S ribosomal subunit, Class II
超分子
名称: Assembly intermediate of the 50S ribosomal subunit, Class II タイプ: complex / ID: 1 / 親要素: 0 / 含まれる分子: #1 / 詳細: Obtained upon depletion of YsxC protein