Centre for Gene Regulation and Expression, University of Dundee, Dundee, UK.
1] Biomedical Sciences Research Complex, University of St. Andrews, St. Andrews, UK. [2] State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China.
Nat Struct Mol Biol. 2015 Aug;22(8):597-602. doi: 10.1038/nsmb.3052. Epub 2015 Jul 6.
RING E3 ligase-catalyzed formation of K63-linked ubiquitin chains by the Ube2V2-Ubc13 E2 complex is required in many important biological processes. Here we report the structure of the RING-domain dimer of rat RNF4 in complex with a human Ubc13∼Ub conjugate and Ube2V2. The structure has captured Ube2V2 bound to the acceptor (priming) ubiquitin with K63 in a position favorable for attack on the linkage between Ubc13 and the donor (second) ubiquitin held in the active 'folded back' conformation by the RING domain of RNF4. We verified the interfaces identified in the structure by in vitro ubiquitination assays of site-directed mutants. To our knowledge, this represents the first view of synthesis of K63-linked ubiquitin chains in which both substrate ubiquitin and ubiquitin-loaded E2 are juxtaposed to allow E3 ligase-mediated catalysis.
RING 结构域 E3 连接酶催化的 Ube2V2-Ubc13 E2 复合物形成的 K63 连接泛素链在许多重要的生物学过程中是必需的。在这里，我们报告了大鼠 RNF4 的 RING 结构域二聚体与人类 Ubc13∼Ub 缀合物和 Ube2V2 的复合物结构。该结构捕获了 Ube2V2 与接受体（引发）泛素结合，K63 处于有利于攻击 Ubc13 和供体（第二）泛素之间连接的位置，供体泛素由 RNF4 的 RING 结构域保持在活性“折叠回”构象中。我们通过针对定点突变的体外泛素化测定验证了结构中鉴定的界面。据我们所知，这代表了首次观察到 K63 连接的泛素链合成，其中两个底物泛素和负载泛素的 E2 并置，以允许 E3 连接酶介导的催化。
Zotero 插件
