Structural insights into 5' flap DNA unwinding and incision by the human FAN1 dimer.
Structural insights into 5' flap DNA unwinding and incision by the human FAN1 dimer.
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对人类 FAN1 二聚体 5 瓣 DNA 解旋和切割的结构见解。
DOI：
10.1038/ncomms6726
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发表时间：
2014
影响因子：
16.6
通讯作者：
Xiong,Yong
中科院分区：
文献类型：
--
作者：
Zhao,Qi;Xue,Xiaoyu;Longerich,Simonne;Sung,Patrick;Xiong,Yong
人FANCD 2相关核酸酶1（FAN 1）是一种DNA结构特异性核酸酶，参与DNA链间交联（ICL）的加工。FAN 1维持基因组稳定性并防止多个器官中的组织衰退，但它在几种癌症亚型中赋予ICL诱导的抗癌药物抗性。在这里，我们报告了三个晶体结构的人FAN 1在复杂的5′皮瓣DNA基板，显示两个FAN 1分子形成一个头到尾的二聚体定位病变，定向的DNA和展开的5′皮瓣为随后的切口。生物化学实验进一步验证了我们的FAN 1作用模型，因为破坏蛋白质二聚化、底物方向或瓣解旋的结构信息突变会损害结构特异性核酸酶活性。我们的工作阐明了FAN 1-DNA损伤识别的基本方面和独特的切割机制。这些结构见解揭示了FAN 1介导的器官变性保护和癌症耐药性的细胞机制。
Human FANCD2-associated nuclease 1 (FAN1) is a DNA structure-specific nuclease involved in the processing of DNA interstrand crosslinks (ICLs). FAN1 maintains genomic stability and prevents tissue decline in multiple organs, yet it confers ICL-induced anti-cancer drug resistance in several cancer subtypes. Here we report three crystal structures of human FAN1 in complex with a 5′ flap DNA substrate, showing that two FAN1 molecules form a head-to-tail dimer to locate the lesion, orient the DNA and unwind a 5′ flap for subsequent incision. Biochemical experiments further validate our model for FAN1 action, as structure-informed mutations that disrupt protein dimerization, substrate orientation or flap unwinding impair the structure-specific nuclease activity. Our work elucidates essential aspects of FAN1-DNA lesion recognition and a unique mechanism of incision. These structural insights shed light on the cellular mechanisms underlying organ degeneration protection and cancer drug resistance mediated by FAN1.