Structural, thermodynamics, and cellular characterization of human centrin 2 interaction with Xeroderma pigmentosum group C protein
Structural, thermodynamics, and cellular characterization of human centrin 2 interaction with Xeroderma pigmentosum group C protein
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DOI：
10.1016/j.jmb.2007.08.046
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发表时间：
2007-11-02
影响因子：
5.6
通讯作者：
Craescu, Constantin T.
中科院分区：
文献类型：
--
作者：
Charbonnier, Jean-Baptiste;Renaud, Emilie;Craescu, Constantin T.
人中心蛋白2（Human centrin 2，HsCen 2）是一种EF-手型钙结合蛋白，在DNA损伤识别过程中起着重要的调控作用。这种生物学作用是通过与着色性干皮病C组（XPC）蛋白C-末端区域的短片段（N847-R863）结合介导的。这项工作提出了一个详细的结构和能量表征的HsCen 2/XPC相互作用。使用截短形式的HsCen 2，我们获得了与来自XPC的肽N847-R863的复合物的高分辨率（1.8埃）X射线结构。界面的结构和热力学分析揭示了静电和非极性分子间相互作用的存在，但结合能主要是由非极性庞大的侧链到HsCen 2 C-末端结构域的疏水口袋中的埋葬决定的。与各种肽变体的结合研究表明，XPC残基W848和L 851构成了关键的锚定侧链。这使我们能够定义一个最小的中心蛋白结合肽的五个残基的变体，占约75%的两种蛋白质之间的相互作用的总自由能。HeLa细胞中的免疫荧光成像表明，HsCen 2结合到完整的XPC蛋白可以在活细胞中观察到，并确定了相同的界面残基中确定的X-射线结构的复合物。XPC的过表达通过诱导中心蛋白分子从细胞质易位到细胞核来扰乱HsCen 2的细胞分布。目前的数据证实，中心蛋白/XPC肽复合物的体外结构特征与细胞环境高度相关。(C)2007爱思唯尔有限公司保留所有权利。
Human centrin 2 (HsCen2), an EF-hand calcium binding protein, plays a regulatory role in the DNA damage recognition during the first steps of the nucleotide excision repair. This biological action is mediated by the binding to a short fragment (N847-R863) from the C-terminal region of xeroderma pigmentosum group C (XPC) protein. This work presents a detailed structural and energetic characterization of the HsCen2/XPC interaction. Using a truncated form of HsCen2 we obtained a high resolution (1.8 angstrom) X-ray structure of the complex with the peptide N847-R863 from XPC. Structural and thermodynamic analysis of the interface revealed the existence of both electrostatic and apolar inter-molecular interactions, but the binding energy is mainly determined by the burial of apolar bulky side-chains into the hydrophobic pocket of the HsCen2 C-terminal domain. Binding studies with various peptide variants showed that XPC residues W848 and L851 constitute the critical anchoring side-chains. This enabled us to define a minimal centrin binding peptide variant of five residues, which accounts for about 75% of the total free energy of interaction between the two proteins. Immunofluorescence imaging in HeLa cells demonstrated that HsCen2 binding to the integral XPC protein may be observed in living cells, and is determined by the same interface residues identified in the X-ray structure of the complex. Overexpression of XPC perturbs the cellular distribution of HsCen2, by inducing a translocation of centrin molecules from the cytoplasm to the nucleus. The present data confirm that the in vitro structural features of the centrin/XPC peptide complex are highly relevant to the cellular context. (C) 2007 Elsevier Ltd. All rights reserved.