Strand-specific Recognition of DNA Damages by XPD Provides Insights into Nucleotide Excision Repair Substrate Versatility
Strand-specific Recognition of DNA Damages by XPD Provides Insights into Nucleotide Excision Repair Substrate Versatility
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DOI：
10.1074/jbc.m113.523001
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发表时间：
2014-02-07
影响因子：
4.8
通讯作者：
Tessmer, Ingrid
中科院分区：
文献类型：
--
作者：
Buechner, Claudia N.;Heil, Korbinian;Tessmer, Ingrid
背景：XPD对于核苷酸切除修复（NER）系统识别DNA损伤是重要的。结果：根据病变类型，XPD识别蛋白质易位或非易位DNA链上的病变。结论：XPD对不同类型的损伤采用不同的识别策略。重要性：不同的损伤特异性识别方法可以增强NER的非常广泛的靶谱。DNA损伤的识别和去除对于细胞和生物体的生存能力是必不可少的。核苷酸切除修复（NER）是人类修复致癌紫外线辐射诱导的DNA光产物（如环丁烷嘧啶二聚体）的唯一机制。NER的广泛底物通用性还包括各种大体积DNA加合物等。已经提出5-3解旋酶XPD（着色性干皮病D组）蛋白在损伤验证中起决定性作用。然而，尽管最近的进展，如DNA结合通道和蛋白质中的中心孔，通过它的DNA是线程，以及一个专用的损伤识别口袋附近的孔，在真核NER的靶位点识别和验证的确切过程仍然难以捉摸。我们通过原子力显微镜进行的单分子分析首次揭示了XPD利用不同的识别策略来验证结构多样的病变。大体积的荧光素损伤优先检测易位链，而相反的链偏好观察到的环丁烷嘧啶二聚体病变。然而，这两种状态导致所得特定复合物中的类似构象变化，表明合并为最终验证状态，这可能随后触发进一步NER蛋白的募集。
Background: XPD is important for DNA lesion recognition by the nucleotide excision repair (NER) system. Results: Dependent on the lesion type, XPD recognizes lesions either on the protein-translocated or on the nontranslocated DNA strand. Conclusion: XPD employs different recognition strategies for different types of damage. Significance: Different lesion-specific recognition approaches may enhance the remarkably broad target spectrum of NER.Recognition and removal of DNA damages is essential for cellular and organismal viability. Nucleotide excision repair (NER) is the sole mechanism in humans for the repair of carcinogenic UV irradiation-induced photoproducts in the DNA, such as cyclobutane pyrimidine dimers. The broad substrate versatility of NER further includes, among others, various bulky DNA adducts. It has been proposed that the 5-3 helicase XPD (xeroderma pigmentosum group D) protein plays a decisive role in damage verification. However, despite recent advances such as the identification of a DNA-binding channel and central pore in the protein, through which the DNA is threaded, as well as a dedicated lesion recognition pocket near the pore, the exact process of target site recognition and verification in eukaryotic NER still remained elusive. Our single molecule analysis by atomic force microscopy reveals for the first time that XPD utilizes different recognition strategies to verify structurally diverse lesions. Bulky fluorescein damage is preferentially detected on the translocated strand, whereas the opposite strand preference is observed for a cyclobutane pyrimidine dimer lesion. Both states, however, lead to similar conformational changes in the resulting specific complexes, indicating a merge to a final verification state, which may then trigger the recruitment of further NER proteins.