ジャーナル: Nature / 年: 2023 タイトル: Structure of the native myosin filament in the relaxed cardiac sarcomere. 著者: Davide Tamborrini / Zhexin Wang / Thorsten Wagner / Sebastian Tacke / Markus Stabrin / Michael Grange / Ay Lin Kho / Martin Rees / Pauline Bennett / Mathias Gautel / Stefan Raunser / 要旨: The thick filament is a key component of sarcomeres, the basic units of striated muscle. Alterations in thick filament proteins are associated with familial hypertrophic cardiomyopathy and other ...The thick filament is a key component of sarcomeres, the basic units of striated muscle. Alterations in thick filament proteins are associated with familial hypertrophic cardiomyopathy and other heart and muscle diseases. Despite the central importance of the thick filament, its molecular organization remains unclear. Here we present the molecular architecture of native cardiac sarcomeres in the relaxed state, determined by cryo-electron tomography. Our reconstruction of the thick filament reveals the three-dimensional organization of myosin, titin and myosin-binding protein C (MyBP-C). The arrangement of myosin molecules is dependent on their position along the filament, suggesting specialized capacities in terms of strain susceptibility and force generation. Three pairs of titin-α and titin-β chains run axially along the filament, intertwining with myosin tails and probably orchestrating the length-dependent activation of the sarcomere. Notably, whereas the three titin-α chains run along the entire length of the thick filament, titin-β chains do not. The structure also demonstrates that MyBP-C bridges thin and thick filaments, with its carboxy-terminal region binding to the myosin tails and directly stabilizing the OFF state of the myosin heads in an unforeseen manner. These results provide a foundation for future research investigating muscle disorders involving sarcomeric components.
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 / 集束イオンビーム - 電流: 0.05 / 集束イオンビーム - 時間: 60 / 集束イオンビーム - 温度: 90 K / 集束イオンビーム - Initial thickness: 1000 / 集束イオンビーム - 最終 厚さ: 180 集束イオンビーム - 詳細: The value given for _em_focused_ion_beam.instrument is FEI Aquilos. This is not in a list of allowed values {'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
撮影
フィルム・検出器のモデル: GATAN K3 BIOQUANTUM (6k x 4k) 平均電子線量: 3.4 e/Å2