ジャーナル: Nat Commun / 年: 2025 タイトル: Coupling of ribosome biogenesis and translation initiation in human mitochondria. 著者: Marleen Heinrichs / Anna Franziska Finke / Shintaro Aibara / Angelique Krempler / Angela Boshnakovska / Peter Rehling / Hauke S Hillen / Ricarda Richter-Dennerlein / 要旨: Biogenesis of mitoribosomes requires dedicated chaperones, RNA-modifying enzymes, and GTPases, and defects in mitoribosome assembly lead to severe mitochondriopathies in humans. Here, we characterize ...Biogenesis of mitoribosomes requires dedicated chaperones, RNA-modifying enzymes, and GTPases, and defects in mitoribosome assembly lead to severe mitochondriopathies in humans. Here, we characterize late-step assembly states of the small mitoribosomal subunit (mtSSU) by combining genetic perturbation and mutagenesis analysis with biochemical and structural approaches. Isolation of native mtSSU biogenesis intermediates via a FLAG-tagged variant of the GTPase MTG3 reveals three distinct assembly states, which show how factors cooperate to mature the 12S rRNA. In addition, we observe four distinct primed initiation mtSSU states with an incompletely matured rRNA, suggesting that biogenesis and translation initiation are not mutually exclusive processes but can occur simultaneously. Together, these results provide insights into mtSSU biogenesis and suggest a functional coupling between ribosome biogenesis and translation initiation in human mitochondria.
全体 : Translation-initiation state of human mitochondrial ribosome smal...
全体
名称: Translation-initiation state of human mitochondrial ribosome small subunit (State D)
要素
複合体: Translation-initiation state of human mitochondrial ribosome small subunit (State D)
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超分子 #1: Translation-initiation state of human mitochondrial ribosome smal...
超分子
名称: Translation-initiation state of human mitochondrial ribosome small subunit (State D) タイプ: complex / ID: 1 / 親要素: 0 詳細: Translation-initiation mtSSU intermediate with immature h44 and in complex with mtIF3.
モデル: Quantifoil R3.5/1 / 材質: COPPER / 支持フィルム - #0 - Film type ID: 1 / 支持フィルム - #0 - 材質: CARBON / 支持フィルム - #0 - トポロジー: HOLEY / 支持フィルム - #1 - Film type ID: 2 / 支持フィルム - #1 - 材質: CARBON / 支持フィルム - #1 - トポロジー: CONTINUOUS / 前処理 - タイプ: GLOW DISCHARGE / 詳細: The grid was precoated with a 2-3 nm carbon layer.
凍結
凍結剤: ETHANE / チャンバー内湿度: 95 % / チャンバー内温度: 277.15 K / 装置: FEI VITROBOT MARK IV
詳細
The sample was crosslinked with 0.15% glutaraldehyde for 10 min on ice. The reaction was stopped by adding 50 mM lysine pH 7.5 and 50 mM aspartate pH 7.5, and subsequently desalted against the final buffer prior to vitrification.
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電子顕微鏡法
顕微鏡
TFS KRIOS
撮影
フィルム・検出器のモデル: GATAN K3 BIOCONTINUUM (6k x 4k) 平均露光時間: 3.0 sec. / 平均電子線量: 40.0 e/Å2
電子線
加速電圧: 300 kV / 電子線源: FIELD EMISSION GUN
電子光学系
照射モード: OTHER / 撮影モード: BRIGHT FIELD / Cs: 2.7 mm / 最大 デフォーカス(公称値): 1.6 µm / 最小 デフォーカス(公称値): 0.6 µm / 倍率(公称値): 81000