DNA photolyases and SP lyase: structure and mechanism of light-dependent and independent DNA lyases
DNA photolyases and SP lyase: structure and mechanism of light-dependent and independent DNA lyases
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DOI：
10.1016/j.sbi.2012.10.002
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发表时间：
2012-12-01
影响因子：
6.8
通讯作者：
Benjdia, Alhosna
中科院分区：
文献类型：
--
作者：
Benjdia, Alhosna
光对许多关键的生物过程至关重要，包括视觉，昼夜节律，光合作用和DNA修复。DNA光解酶利用光能和完全还原的黄素辅因子来修复主要的UV诱导的DNA损伤，即顺式-顺式环丁烷嘧啶二聚体（CPD）和嘧啶-嘧啶酮（6-4）光产物。催化涉及两个光反应，光活化导致黄素辅因子转化为其催化活性形式，而光修复的效率取决于光捕获天线生色团。非常有趣的是，在细菌孢子中发现了一种替代性的、不依赖于光的直接逆转机制来修复明显的光损伤，该机制由孢子光产物裂解酶催化。这种自由基SAM酶使用铁硫簇和S-腺苷-L-甲硫氨酸（SAM）将特定的光产物（所谓的孢子光产物（SP））分解为两个胸苷残基。最近解决的SP裂解酶的晶体结构提供了新的见解，这种独特的DNA修复机制，并允许与DNA光解酶的详细比较。DNA光解酶和SP裂解酶之间的相似性以及分歧强调在这方面的审查。
Light is essential for many critical biological processes including vision, circadian rhythms, photosynthesis and DNA repair. DNA photolyases use light energy and a fully reduced flavin cofactor to repair the major UV-induced DNA damages, the cis-syn cyclobutane pyrimidine dimers (CPDs) and the pyrimidine-pyrimidone (6-4) photoproducts. Catalysis involves two photoreactions, the photoactivation which leads to the conversion of the flavin cofactor to its catalytic active form and the photorepair whose efficiency depends on a light-harvesting antenna chromophore. Very interestingly, an alternative and light-independent direct reversal mechanism to repair a distinct photolesion is found in bacterial spores, catalyzed by spore photoproduct lyase. This radical SAM enzyme uses an iron-sulfur cluster and S-adenosyl-L-methionine (SAM) to split a specific photoproduct, the so-called spore photoproduct (SP), back to two thymidine residues. The recently solved crystal structure of SP lyase provides new insights into this unique DNA repair mechanism and allows a detailed comparison with DNA photolyases. Similarities as well as divergences between DNA photolyases and SP lyase are highlighted in this review.