Akutsu Masato, Kawasaki Masato, Katoh Yohei, Shiba Tomoo, Yamaguchi Yoshiki, Kato Ryuichi, Kato Koichi, Nakayama Kazuhisa, Wakatsuki Soichi
Structural Biology Research Center, Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki, Japan
FEBS Lett. 2005 Oct 10;579(24):5385-91. doi: 10.1016/j.febslet.2005.08.076.
Tom1 (Target of Myb1) is suggested to be involved in the transport of ubiquitinated proteins, through the interaction of its GAT (GGA and Tom1) domain with ubiquitin. Here, we demonstrate that the three-helix bundle of Tom1-GAT has two ubiquitin-binding sites recognizing the hydrophobic Ile44 surface of ubiquitin. The complex crystal structure demonstrates that the first site is a hydrophobic patch on helices alpha1 and alpha2. NMR and biochemical data revealed that the N-terminal half of helix alpha3 of Tom1-GAT constitutes the second, stronger binding site. The double-sided ubiquitin binding enhances the efficiency of recognition of ubiquitinated proteins by Tom1.
Tom1（Myb1的靶点）被认为通过其GAT（GGA和Tom1）结构域与泛素的相互作用参与泛素化蛋白的转运。在此，我们证明Tom1-GAT的三螺旋束有两个识别泛素疏水Ile44表面的泛素结合位点。复合物晶体结构表明第一个位点是α1和α2螺旋上的一个疏水补丁。核磁共振和生化数据显示Tom1-GAT的α3螺旋的N端一半构成第二个更强的结合位点。双面泛素结合提高了Tom1对泛素化蛋白的识别效率。
