ジャーナル: Nat Plants / 年: 2019 タイトル: Biogenic regions of cyanobacterial thylakoids form contact sites with the plasma membrane. 著者: Anna Rast / Miroslava Schaffer / Sahradha Albert / William Wan / Stefan Pfeffer / Florian Beck / Jürgen M Plitzko / Jörg Nickelsen / Benjamin D Engel / 要旨: Little is known about how the photosynthetic machinery is arranged in time and space during the biogenesis of thylakoid membranes. Using in situ cryo-electron tomography to image the three- ...Little is known about how the photosynthetic machinery is arranged in time and space during the biogenesis of thylakoid membranes. Using in situ cryo-electron tomography to image the three-dimensional architecture of the cyanobacterium Synechocystis, we observed that the tips of multiple thylakoids merge to form a substructure called the 'convergence membrane'. This high-curvature membrane comes into close contact with the plasma membrane at discrete sites. We generated subtomogram averages of 70S ribosomes and array-forming phycobilisomes, then mapped these structures onto the native membrane architecture as markers for protein synthesis and photosynthesis, respectively. This molecular localization identified two distinct biogenic regions in the thylakoid network: thylakoids facing the cytosolic interior of the cell that were associated with both marker complexes, and convergence membranes that were decorated by ribosomes but not phycobilisomes. We propose that the convergence membranes perform a specialized biogenic function, coupling the synthesis of thylakoid proteins with the integration of cofactors from the plasma membrane and the periplasmic space.
凍結剤: ETHANE-PROPANE / チャンバー内湿度: 90 % / チャンバー内温度: 297 K / 装置: FEI VITROBOT MARK IV / 詳細: Blotting time: 10 sec Blot force: 10.
詳細
Vitrious Synechocystis cell milled with a Ga2+ focused ion beam.
切片作成
集束イオンビーム - 装置: OTHER / 集束イオンビーム - イオン: OTHER / 集束イオンビーム - 電圧: 30 kV / 集束イオンビーム - 電流: 0.03 nA / 集束イオンビーム - 時間: 3600 sec. / 集束イオンビーム - 温度: 93 K / 集束イオンビーム - Initial thickness: 2000 nm / 集束イオンビーム - 最終 厚さ: 150 nm 集束イオンビーム - 詳細: The value given for _emd_sectioning_focused_ion_beam.instrument is FEI Quanta FIB. This is not in a list of allowed values set(['DB235', 'OTHER']) so OTHER is written into the XML file.
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電子顕微鏡法
顕微鏡
FEI TITAN KRIOS
特殊光学系
エネルギーフィルター - 名称: GIF Quantum LS / エネルギーフィルター - スリット幅: 20 eV
撮影
フィルム・検出器のモデル: GATAN K2 SUMMIT (4k x 4k) 検出モード: COUNTING / デジタル化 - サイズ - 横: 3838 pixel / デジタル化 - サイズ - 縦: 3710 pixel / 平均露光時間: 1.5 sec. / 平均電子線量: 1.5 e/Å2 詳細: Images were collected in movie-mode at 12 frames per second. Higher tilts had longer exposures.