Schnuchel A, Wiltscheck R, Eichinger L, Schleicher M, Holak T A
Max-Planck-Institute for Biochemistry, Martinsried, F.R.G.
J Mol Biol. 1995 Mar 17;247(1):21-7. doi: 10.1006/jmbi.1994.0118.
The three-dimensional structure of domain 2 of severin in aqueous solution was determined by nuclear magnetic resonance spectroscopy. Severin is a Ca(2+)-activated actin-binding protein that servers F-actin, nucleates actin assembly, and caps the fast-growing ends of actin filaments. The 114-residue domain consists of a central five-stranded beta-sheet, sandwiched between a parallel four-turn alpha-helix and, on the other face, a roughly perpendicular two-turn alpha-helix. There are two distinct binding sites for Ca2+ located near the N and C termini of the long helix. Conserved residues of the gelsolin-severin family contribute to the apolar core of domain 2 of severin, so that the overall fold of the protein is similar to those of segment 1 of gelsolin and profilins. Together with biochemical experiments, this structure helps to explain how severin interacts with actin.
通过核磁共振光谱法测定了肌割蛋白结构域2在水溶液中的三维结构。肌割蛋白是一种Ca(2+)激活的肌动蛋白结合蛋白，它作用于F-肌动蛋白，引发肌动蛋白组装，并封闭肌动蛋白丝快速生长的末端。这个由114个残基组成的结构域包含一个中央的五链β折叠，夹在一个平行的四圈α螺旋和另一面一个大致垂直的两圈α螺旋之间。在长螺旋的N端和C端附近有两个不同的Ca2+结合位点。凝溶胶蛋白-肌割蛋白家族的保守残基构成了肌割蛋白结构域2的非极性核心，因此该蛋白质的整体折叠与凝溶胶蛋白片段1和肌动蛋白 Profilin的折叠相似。结合生化实验，这个结构有助于解释肌割蛋白如何与肌动蛋白相互作用。
