Pullan Lee, Mullapudi Srinivas, Huang Zhong, Baldwin Philip R, Chin Christopher, Sun Wei, Tsujimoto Susan, Kolodziej Steven J, Stoops James K, Lee J Ching, Waxham M Neal, Bean Andrew J, Penczek Pawel A
Department of Biochemistry and Molecular Biology, The University of Texas-Houston Medical School, 6431 Fannin, Houston, Texas 77030, USA.
Structure. 2006 Apr;14(4):661-71. doi: 10.1016/j.str.2006.01.012.
The structure of the endosomal-associated protein, Hrs, has been determined with cryo-electron microscopy. Hrs interacts with a number of proteins, including SNAP-25 and STAM1, forming a complex that binds ubiquitin moieties. Analytical ultracentrifugation studies revealed that Hrs exists as a hexamer. The symmetry and the structure of the hexameric form of Hrs were determined with the single-particle reconstruction method. Hrs comprises three antiparallel dimers with a central core and distinct caps on either end. Crystal structures of VHS and FYVE domains fit into the Hrs end caps in the EM density map. Thus, the location of domains that interact with the endosomal membrane, the VHS, FYVE, and C-terminal domains, facilitates the anchorage of Hrs to the membrane, initiating the functional processes of Hrs on the endosome. Based on our model, the Hrs hexamer interacts with the membrane and acts as a "master molecule" that presents multiple sites for protein binding.
已通过冷冻电子显微镜确定了内体相关蛋白Hrs的结构。Hrs与多种蛋白质相互作用，包括SNAP-25和STAM1，形成一个结合泛素部分的复合物。分析超速离心研究表明，Hrs以六聚体形式存在。采用单颗粒重建方法确定了Hrs六聚体形式的对称性和结构。Hrs由三个反平行二聚体组成，中间有一个核心，两端有不同的帽。VHS和FYVE结构域的晶体结构在电子显微镜密度图中与Hrs的端帽相契合。因此，与内体膜相互作用的结构域，即VHS、FYVE和C末端结构域的位置，有助于Hrs锚定在膜上，启动Hrs在内体上的功能过程。基于我们的模型，Hrs六聚体与膜相互作用，并作为一个“主分子”，提供多个蛋白质结合位点。
