Two-stage dynamic DNA quality check by xeroderma pigmentosum group C protein
Two-stage dynamic DNA quality check by xeroderma pigmentosum group C protein
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DOI：
10.1038/emboj.2009.187
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发表时间：
2009-08-19
期刊：
影响因子：
11.4
通讯作者：
Naegeli, Hanspeter
中科院分区：
文献类型：
--
作者：
Camenisch, Ulrike;Traeutlein, Daniel;Naegeli, Hanspeter
着色性干皮病C组(XPC)蛋白启动螺旋扭曲的碱基损伤的DNA切除修复。为了了解这个多功能的亚基是如何在正常基因组DNA的巨大背景中搜索异常位置的，我们监测了高分辨率DNA损伤诱导后荧光融合结构的实时重新分布。双向截断分析揭示了一个令人惊讶的短识别热点，类似于人类XPC的15%，它包括两个β-发夹结构域，偏好双链DNA中的非氢键碱基。然而，为了检测活细胞中的损伤位置，这些DNA吸引结构域依赖于邻近的β-转角延伸部分的DNA排斥作用，该作用促进了XPC分子搜索损伤的流动性。这种动态相互作用面的关键功能表现为一种定点电荷反转，它导致与天然DNA的亲和力增加，核迁移率下降，修复效率降低。这些研究揭示了一个两阶段的识别过程，即XPC蛋白首先部署一个动态的传感器接口来快速询问双螺旋，从而在最终安装更静态的修复启动复合体之前形成一个瞬时的识别中间产物。EMBO期刊(2009)28,2387-2399。DOI：10.1038/Intemj.2009.187；2009年7月16日在线发布
Xeroderma pigmentosum group C (XPC) protein initiates the DNA excision repair of helix-distorting base lesions. To understand how this versatile subunit searches for aberrant sites within the vast background of normal genomic DNA, the real-time redistribution of fluorescent fusion constructs was monitored after high-resolution DNA damage induction. Bidirectional truncation analyses disclosed a surprisingly short recognition hotspot, comprising similar to 15% of human XPC, that includes two beta-hairpin domains with a preference for non-hydrogen-bonded bases in double-stranded DNA. However, to detect damaged sites in living cells, these DNA-attractive domains depend on the partially DNA-repulsive action of an adjacent beta-turn extension that promotes the mobility of XPC molecules searching for lesions. The key function of this dynamic interaction surface is shown by a site-directed charge inversion, which results in increased affinity for native DNA, retarded nuclear mobility and diminished repair efficiency. These studies reveal a two-stage discrimination process, whereby XPC protein first deploys a dynamic sensor interface to rapidly interrogate the double helix, thus forming a transient recognition intermediate before the final installation of a more static repair-initiating complex. The EMBO Journal (2009) 28, 2387-2399. doi:10.1038/emboj.2009.187; Published online 16 July 2009