Hefei National Laboratory for Physical Sciences at Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, P R China.
PLoS One. 2013;8(1):e53639. doi: 10.1371/journal.pone.0053639. Epub 2013 Jan 9.
The ADF/cofilin family has been characterized as a group of actin-binding proteins critical for controlling the assembly of actin within the cells. In this study, the solution structure of the ADF/cofilin from Trypanosoma brucei (TbCof) was determined by NMR spectroscopy. TbCof adopts the conserved ADF/cofilin fold with a central β-sheet composed of six β-strands surrounded by five α-helices. Isothermal titration calorimetry experiments denoted a submicromolar affinity between TbCof and G-actin, and the affinity between TbCof and ADP-G-actin was five times higher than that between TbCof and ATP-G-actin at low ionic strength. The results obtained from electron microscopy and actin filament sedimentation assays showed that TbCof depolymerized but did not co-sediment with actin filaments and its ability of F-actin depolymerization was pH independent. Similar to actin, TbCof was distributed throughout the cytoplasm. All our data indicate a structurally and functionally conserved ADF/cofilin from Trypanosoma brucei.
ADF/cofilin 家族被认为是一组细胞内控制肌动蛋白组装的肌动蛋白结合蛋白，对其具有重要作用。在这项研究中，通过 NMR 光谱法确定了来自布氏锥虫（Trypanosoma brucei）的 ADF/cofilin（TbCof）的溶液结构。TbCof 采用保守的 ADF/cofilin 折叠结构，由六个β-折叠组成的中心β-片层被五个α-螺旋包围。等温滴定量热实验表明，TbCof 与 G-肌动蛋白之间具有亚微摩尔亲和力，并且在低离子强度下，TbCof 与 ADP-G-肌动蛋白的亲和力比 TbCof 与 ATP-G-肌动蛋白的亲和力高五倍。电子显微镜和肌动蛋白丝沉淀实验的结果表明，TbCof 解聚但不与肌动蛋白丝共沉淀，并且其 F-肌动蛋白解聚能力与 pH 无关。与肌动蛋白相似，TbCof 分布在整个细胞质中。我们所有的数据表明，来自布氏锥虫的 ADF/cofilin 在结构和功能上都是保守的。
