ジャーナル: Nature / 年: 2020 タイトル: Structure of the shutdown state of myosin-2. 著者: Charlotte A Scarff / Glenn Carrington / David Casas-Mao / Joseph M Chalovich / Peter J Knight / Neil A Ranson / Michelle Peckham / 要旨: Myosin-2 is essential for processes as diverse as cell division and muscle contraction. Dephosphorylation of its regulatory light chain promotes an inactive, 'shutdown' state with the filament- ...Myosin-2 is essential for processes as diverse as cell division and muscle contraction. Dephosphorylation of its regulatory light chain promotes an inactive, 'shutdown' state with the filament-forming tail folded onto the two heads, which prevents filament formation and inactivates the motors. The mechanism by which this happens is unclear. Here we report a cryo-electron microscopy structure of shutdown smooth muscle myosin with a resolution of 6 Å in the head region. A pseudo-atomic model, obtained by flexible fitting of crystal structures into the density and molecular dynamics simulations, describes interaction interfaces at the atomic level. The N-terminal extension of one regulatory light chain interacts with the tail, and the other with the partner head, revealing how the regulatory light chains stabilize the shutdown state in different ways and how their phosphorylation would allow myosin activation. Additional interactions between the three segments of the coiled coil, the motor domains and the light chains stabilize the shutdown molecule. The structure of the lever in each head is competent to generate force upon activation. This shutdown structure is relevant to all isoforms of myosin-2 and provides a framework for understanding their disease-causing mutations.
凍結剤: ETHANE / チャンバー内湿度: 100 % / チャンバー内温度: 281 K / 装置: FEI VITROBOT MARK IV / 詳細: Blot force 6, blot time 3 seconds.
詳細
Smooth muscle myosin from turkey gizzard, stored under liquid nitrogen, was thawed quickly. MgATP was added before dilution into the final buffer conditions stated below