Recognition and repair of UV lesions in loop structures of duplex DNA by DASH-type cryptochrome
Recognition and repair of UV lesions in loop structures of duplex DNA by DASH-type cryptochrome
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DOI：
10.1073/pnas.0805830106
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发表时间：
2008-12-30
影响因子：
11.1
通讯作者：
Essen, Lars-Oliver
中科院分区：
文献类型：
--
作者：
Pokorny, Richard;Klar, Tobias;Essen, Lars-Oliver
DNA光解酶和隐色素酶(CRY)形成了一个黄素蛋白家族，它们分别利用蓝色/UV-A区域的光能修复紫外线诱导的DNA损伤或发出信号。最近，有研究表明，DASH的隐色素亚类成员修复紫外线损伤的单链DNA中的环丁烷嘧啶二聚体(CPDS)。在这里，我们报道了在单链DNA中带有原位修复的CPD底物的拟南芥隐花色素3的晶体结构。该结构显示出类似于传统DNA光解酶的结合模式。此外，如果CPD损伤存在于环状结构中，则双链DNA中的CPD损伤被结合并以与单链DNA中相同的效率修复。综上所述，这些数据表明，DASH隐色素像传统的光解酶一样催化光驱动的DNA修复，但缺乏有效的翻转机制来与双链DNA中的CPD损伤相互作用。
DNA photolyases and cryptochromes (cry) form a family of flavoproteins that use light energy in the blue/UV-A region for the repair of UV-induced DNA lesions or for signaling, respectively. Very recently, it was shown that members of the DASH cryptochrome subclade repair specifically cyclobutane pyrimidine dimers (CPDs) in UV-damaged single-stranded DNA. Here, we report the crystal structure of Arabidopsis cryptochrome 3 with an in-situ-repaired CPD substrate in single-stranded DNA. The structure shows a binding mode similar to that of conventional DNA photolyases. Furthermore, CPD lesions in double-stranded DNA are bound and repaired with similar efficiency as in single-stranded DNA if the CPD lesion is present in a loop structure. Together, these data reveal that DASH cryptochromes catalyze light-driven DNA repair like conventional photolyases but lack an efficient flipping mechanism for interaction with CPD lesions within duplex DNA.