Emil Aaltonen, Sigrid Juselius, and Jane and Aatos Erkko foundations
引用
ジャーナル: Proc Natl Acad Sci U S A / 年: 2017 タイトル: Near-atomic structure of jasplakinolide-stabilized malaria parasite F-actin reveals the structural basis of filament instability. 著者: Sabrina Pospich / Esa-Pekka Kumpula / Julian von der Ecken / Juha Vahokoski / Inari Kursula / Stefan Raunser / 要旨: During their life cycle, apicomplexan parasites, such as the malaria parasite , use actomyosin-driven gliding motility to move and invade host cells. For this process, actin filament length and ...During their life cycle, apicomplexan parasites, such as the malaria parasite , use actomyosin-driven gliding motility to move and invade host cells. For this process, actin filament length and stability are temporally and spatially controlled. In contrast to canonical actin, actin 1 (Act1) does not readily polymerize into long, stable filaments. The structural basis of filament instability, which plays a pivotal role in host cell invasion, and thus infectivity, is poorly understood, largely because high-resolution structures of Act1 filaments were missing. Here, we report the near-atomic structure of jasplakinolide (JAS)-stabilized Act1 filaments determined by electron cryomicroscopy. The general filament architecture is similar to that of mammalian F-actin. The high resolution of the structure allowed us to identify small but important differences at inter- and intrastrand contact sites, explaining the inherent instability of apicomplexan actin filaments. JAS binds at regular intervals inside the filament to three adjacent actin subunits, reinforcing filament stability by hydrophobic interactions. Our study reveals the high-resolution structure of a small molecule bound to F-actin, highlighting the potential of electron cryomicroscopy for structure-based drug design. Furthermore, our work serves as a strong foundation for understanding the structural design and evolution of actin filaments and their function in motility and host cell invasion of apicomplexan parasites.
凍結剤: ETHANE / チャンバー内湿度: 97 % / チャンバー内温度: 298 K / 装置: GATAN CRYOPLUNGE 3 詳細: Sample (2 uL of JAS-stabilized F-actin solution) was applied to a glow-discharged holey carbon grid, incubated for 30 s and manually blotted for 4 s from the backside with filter paper..
詳細
Twist (degree) 167.5 Rise (A) 27.4
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電子顕微鏡法
顕微鏡
FEI TITAN KRIOS
詳細
Cs corrected microscope
撮影
フィルム・検出器のモデル: FEI FALCON II (4k x 4k) 検出モード: INTEGRATING / デジタル化 - 画像ごとのフレーム数: 1-4 / 実像数: 1634 / 平均露光時間: 1.5 sec. / 平均電子線量: 110.0 e/Å2
モデルのタイプ: INSILICO MODEL 詳細: An inital model was generated by first fitting a homology model into a previously obtained map at 7 A resolution and afterwards creating an electron density map from the model and filtering it to 20 A.