School of Life Sciences, State Key Laboratory of Protein and Plant Gene Research, Peking University, Beijing 100871, China.
FEBS Lett. 2011 Nov 4;585(21):3396-402. doi: 10.1016/j.febslet.2011.09.042. Epub 2011 Oct 12.
As a class of molecular chaperones, small heat shock proteins (sHsps) usually exist as multi-subunit spherical oligomers. In this study, we report that AgsA, a sHsp of Salmonella enterica serovar Typhimurium, spontaneously forms fibrils in vitro. These fibrils tend to be formed at elevated temperature and do not share the characteristics of amyloid. Interestingly, the fibril-forming AgsA is able to suppress the dithiothreitol-induced aggregation of insulin efficiently within a certain range of temperature. During this process, AgsA fibrils disappear and spherical complexes form between AgsA and insulin molecules. These data suggest that AgsA fibrils may represent a distinctive type of structural and functional form of sHsp from spherical oligomers. Our study provides new insights into sHsp structures and chaperone functions.
作为一类分子伴侣，小分子热休克蛋白（sHsps）通常以多亚基球形寡聚体的形式存在。在这项研究中，我们报告称，沙门氏菌血清型鼠伤寒杆菌的 sHsp AgsA 可在体外自发形成纤维。这些纤维往往在高温下形成，并且不具有淀粉样蛋白的特征。有趣的是，形成纤维的 AgsA 能够在一定温度范围内有效抑制二硫苏糖醇诱导的胰岛素聚集。在此过程中，AgsA 纤维消失，AgsA 和胰岛素分子之间形成球形复合物。这些数据表明，AgsA 纤维可能代表 sHsp 从球形寡聚体到纤维的一种独特的结构和功能形式。我们的研究为 sHsp 结构和伴侣功能提供了新的见解。
