Structural and biochemical studies of the open state of Lys48-linked diubiquitin.
Structural and biochemical studies of the open state of Lys48-linked diubiquitin.
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Lys48 连接的双泛素开放状态的结构和生化研究。
DOI：
10.1016/j.bbamcr.2012.04.003
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发表时间：
2012-11
期刊：
影响因子：
--
通讯作者：
Fushman D
中科院分区：
文献类型：
--
作者：
Lai MY;Zhang D;Laronde-Leblanc N;Fushman D
泛素（Ubiquitin，Ub）是一种在真核生物中高度保守的小分子蛋白质，参与真核细胞生物学的各个方面。由共价连接的Ub单体组装的聚合物链在调节宿主细胞过程中充当分子信号。我们以前的研究表明，Lys 48连接的二-和四-Ub链在近生理条件下的主要状态是一个封闭的构象，其中Ub/Ub界面是由相邻Ub单元的疏水表面残基形成的。由于这些残基参与了与大多数Ub结合蛋白的（聚）Ub相互作用，因此它们在Ub/Ub界面处的螯合使得聚Ub结合不合格的闭合构象。因此，开放构象的存在以及打开和关闭Ub/Ub界面的结构域间运动对于Lys 48连接的polyUb被其受体识别至关重要。polyUb信号的构象特性的知识是必不可少的，为我们了解其特异性识别的各种Ub受体。尽管其功能的重要性，开放状态的Lys 48连接的链的特点很差。在这里，我们报告的晶体结构的开放状态的Lys 48连接二Ub。此外，使用NMR，我们研究了该链的开放状态（在pH 4.5）与Lys 48-连接选择性受体，穿梭蛋白hHR 23 a的UBA 2结构域的相互作用。我们的研究结果表明，二Ub结合UBA 2在相同的模式和可比的亲和力作为封闭状态。我们的数据表明polyUb信号识别的机制，其中Ub结合蛋白选择特定的构象的polyUb链构象可用的合奏。
Ubiquitin (Ub) is a small protein highly conserved among eukaryotes and involved in practically all aspects of eukaryotic cell biology. Polymeric chains assembled of covalently-linked Ub monomers function as molecular signals in the regulation of a host of cellular processes. Our previous studies have shown that the predominant state of Lys48-linked di- and tetra-Ub chains at near-physiological conditions is a closed conformation, in which the Ub/Ub interface is formed by the hydrophobic surface residues of the adjacent Ub units. Because these very residues are involved in (poly)Ub interactions with the majority of Ub-binding proteins, their sequestration at the Ub/Ub interface renders the closed conformation of polyUb binding incompetent. Thus the existence of open conformation(s) and the interdomain motions opening and closing the Ub/Ub interface is critical for the recognition of Lys48-linked polyUb by its receptors. Knowledge of the conformational properties of polyUb signal is essential for our understanding of its specific recognition by various Ub-receptors. Despite their functional importance, open states of Lys48-linked chains are poorly characterized. Here we report a crystal structure of the open state of Lys48-linked di-Ub. Moreover, using NMR, we examined interactions of the open state of this chain (at pH4.5) with a Lys48-linkage-selective receptor, the UBA2 domain of a shuttle protein hHR23a. Our results show that di-Ub binds UBA2 in the same mode and with comparable affinity as the closed state. Our data suggest a mechanism for polyUb signal recognition, whereby Ub-binding proteins select specific conformations out of the available ensemble of polyUb chain conformations.
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影响因子：
2.9
作者：
Beal, RE;Toscano-Cantaffa, D;Pickart, CM
通讯作者：
Pickart, CM
影响因子：
5.6
作者：
Haririnia, Aydin;D'Onofrio, Mariapina;Fushman, David
通讯作者：
Fushman, David
影响因子：
2.9
作者：
Haldeman, MT;Xia, G;Pickart, CM
通讯作者：
Pickart, CM
DOI：
10.3410/b3-26
发表时间：
2011
期刊：
F1000 biology reports
影响因子：
--
作者：
Fushman D;Wilkinson KD
通讯作者：
Wilkinson KD
DOI：
10.1107/s0907444903008126
发表时间：
2003-07-01
影响因子：
2.2
作者：
Potterton, E;Briggs, P;Dodson, E
通讯作者：
Dodson, E