Narayan Kartik, Chumnarnsilpa Sakesit, Choe Han, Irobi Edward, Urosev Dunja, Lindberg Uno, Schutt Clarence E, Burtnick Leslie D, Robinson Robert C
Department of Medical Biochemistry and Microbiology, Uppsala University, Box 582, 751 23 Uppsala, Sweden.
FEBS Lett. 2003 Sep 25;552(2-3):82-5. doi: 10.1016/s0014-5793(03)00933-5.
Gelsolin requires activation to carry out its severing and capping activities on F-actin. Here, we present the structure of the isolated C-terminal half of gelsolin (G4-G6) at 2.0 A resolution in the presence of Ca(2+) ions. This structure completes a triptych of the states of activation of G4-G6 that illuminates its role in the function of gelsolin. Activated G4-G6 displays an open conformation, with the actin-binding site on G4 fully exposed and all three type-2 Ca(2+) sites occupied. Neither actin nor the type-l Ca(2+), which normally is sandwiched between actin and G4, is required to achieve this conformation.
凝溶胶蛋白需要激活才能对F-肌动蛋白进行切断和封端活动。在此，我们展示了在钙离子存在下，分辨率为2.0埃的分离的凝溶胶蛋白C端半段（G4-G6）的结构。该结构完善了G4-G6激活状态的三联图，阐明了其在凝溶胶蛋白功能中的作用。激活的G4-G6呈现开放构象，G4上的肌动蛋白结合位点完全暴露，所有三个2型钙离子位点均被占据。实现这种构象既不需要肌动蛋白，也不需要通常夹在肌动蛋白和G4之间的1型钙离子。
