p15PAF Is an Intrinsically Disordered Protein with Nonrandom Structural Preferences at Sites of Interaction with Other Proteins
p15PAF Is an Intrinsically Disordered Protein with Nonrandom Structural Preferences at Sites of Interaction with Other Proteins
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DOI：
10.1016/j.bpj.2013.12.046
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发表时间：
2014-02-18
影响因子：
3.4
通讯作者：
Blanco, Francisco J.
中科院分区：
文献类型：
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作者：
De Biasio, Alfredo;Ibanez de Opakua, Alain;Blanco, Francisco J.
据我们所知，我们首次对增殖细胞核抗原相关因子 p15 (PAF) 进行了结构表征，表明它是单体且在溶液中本质上无序，但在蛋白质-蛋白质相互作用位点具有非随机构象偏好。 p15(PAF) 是一种 12 kDa 核蛋白，在 DNA 复制过程中充当 DNA 修复的调节因子。 p15(PAF) 基因在多种类型的人类癌症中过度表达。 p15(PAF) 的近乎完整的 NMR 主链分配使我们能够测量 86 个 N-H-N 残余偶极偶合。我们的残余偶极耦合分析揭示了不同区域的非随机构象偏好，包括增殖细胞核抗原相互作用蛋白基序 (PIP-box) 和 KEN-box（由靶向 p15(PAF) 降解的泛素连接酶识别）。根据这些发现，对 N-15 R-2 弛豫率的分析显示这些区域中残基的迁移率相对降低。 p15(PAF) 的实验小角度 X 射线散射曲线与根据局部二级结构元素的存在进行校正的统计线圈系综计算的曲线之间的一致性进一步验证了 p15(PAF) 的结构模型。这些瞬时结构区域与蛋白质-蛋白质相互作用和翻译后修饰位点的重合表明这些结构可能作为 p15(PAF) 的分子识别元件。
We present to our knowledge the first structural characterization of the proliferating-cell-nuclear-antigen-associated factor p15(PAF), showing that it is monomeric and intrinsically disordered in solution but has nonrandom conformational preferences at sites of protein-protein interactions. p15(PAF) is a 12 kDa nuclear protein that acts as a regulator of DNA repair during DNA replication. The p15(PAF) gene is overexpressed in several types of human cancer. The nearly complete NMR backbone assignment of p15(PAF) allowed us to measure 86 N-H-N residual dipolar couplings. Our residual dipolar coupling analysis reveals nonrandom conformational preferences in distinct regions, including the proliferating-cell-nuclear-antigen-interacting protein motif (PIP-box) and the KEN-box (recognized by the ubiquitin ligase that targets p15(PAF) for degradation). In accordance with these findings, analysis of the N-15 R-2 relaxation rates shows a relatively reduced mobility for the residues in these regions. The agreement between the experimental small angle x-ray scattering curve of p15(PAF) and that computed from a statistical coil ensemble corrected for the presence of local secondary structural elements further validates our structural model for p15(PAF). The coincidence of these transiently structured regions with protein-protein interaction and posttranslational modification sites suggests a possible role for these structures as molecular recognition elements for p15(PAF).